Camera with lens barrier apparatus

ABSTRACT

A lens barrier opening/closing mechanism includes of at least two rotating barrier members, each which rotates about a pivot, a drive ring which is driven to rotate about an optical axis, and at least two rotation force transmitting links, each which is supported on the drive ring and is provided with an engaging part which engages with a respective one of the two rotating barrier members. Thus, the engaging part of each of the two rotation force transmitting links is formed with a first section that non-resiliently moves the two rotating barrier members in an opening direction when the drive ring rotates from a position at which the barrier is fully closed, to a position at which the barrier is opened intermediately and resiliently urges the two rotating barrier members in a closing direction by a spring force when the drive ring rotates from the position at which the barrier is opened intermediately to the position at which the barrier is fully closed and a second section that non-resiliently moves the pair of rotating barrier members in the closing direction when the drive ring rotates from the position at which the barrier is fully opened to the position at which the barrier is opened intermediately and resiliently urges the pair of rotating barrier members towards the opening direction by a spring force when the drive ring rotates from the position at which the barrier is opened intermediately to the position at which the barrier is fully opened.

The present application is a divisional of U.S. application Ser. No.08/775,239 filed on Dec. 30, 1996 which is now U.S. Pat. No. 5,842,057issued on Nov. 24, 1998.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a camera provided with a lens barrierapparatus. In particular, the present invention is directed to a lensbarrier apparatus which is provided as a barrier to cover the lens whenthe camera is not in use.

2. Description of the Related Art

A camera may include a lens barrier apparatus that operates such thatwhen the camera is turned ON, a lens barrel containing the lens (or lensgroup) moves from a housed position in which the lens barrier is closed,to a photo-ready position in which the lens barrier is open. Similarly,when the camera is turned OFF, the lens barrel moves from thephoto-ready position in which the barrier apparatus is open, to a housedposition in which the barrier apparatus is closed.

In most cases, including zoom lens cameras, a lens barrel motor isprovided to drive the lens barrel from the housed position to thephoto-ready position. Thus, a conventional method of driving the barrierapparatus is to use the lens barrel motor to open and close the barrierapparatus.

One such method uses a spring-loaded barrier apparatus that is designedsuch that the barrier is constantly urged in the opening direction by aspring. In this case, as the lens barrel moves from the housed positionto the photo-ready position, a catch is released such that a storedspring force is released to open the barrier. Then, when the lens barrelmotor drives the lens barrel from the photo-ready position to the housedposition, the barrier is closed against the force of the spring by a cammechanism or the like and the spring is reset to prepare for the nextopening operation.

With such a barrier apparatus, the motor must operate against the forceof the spring in order to close the barrier. As such, the motor, and inparticular, the contact points between a cam pin and a barrier drivingring are subject to a load. In this case, misalignment of the cam pinand the barrier driving ring could result in a failure. Further, in theparticular case of a zoom lens, in which the lens barrel motor may beused to drive a number of lens barrels, the additional load may requirea larger lens barrel motor.

Since in the above method the opening of the barrier is spring-biased,if the barrel has accidentally been exposed to a sticky liquid, such asjuice or the like, the barrier may not open correctly because the springforce cannot overcome the external sticking force. In this case, alarger than usual force is required at the initial stages of the openingoperation. However, if a stronger spring is used in order to provide alarger force to overcome the external force, the design choicesavailable become more restricted and there is a higher probability offailure because of wear.

The above problem can be overcome if the barrier apparatus includes abarrier motor that drives the barrier apparatus independently. However,this method also has problems in that, for example, the size of thecamera is increased due to the inclusion of an independent barrier motorand the components required for the operation of the barrier motor.Further, with this arrangement, a sensor that determines the conditionof the barrier apparatus is required in order to prevent problems if thebarrier motor fails. For example, if the barrier motor fails but thelens barrel motor does not, the user may not be aware of the problem andmay attempt to take a photograph with the barrier closed, or, store thecamera with the barrier open and damage the lens.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide animproved camera with lens barrier apparatus.

According to a first aspect of the present invention, there is provideda camera with a lens barrier apparatus. The lens barrier apparatusincludes a lens barrier, a lens barrier opening/closing mechanism, and asignal generating device. The signal generating device generates apredetermined signal in response to the opening and closing of the lensbarrier by the lens barrier opening/closing mechanism. In this way, theoperation of the lens barrier apparatus can be monitored based on thesignal.

In particular, the lens barrier apparatus may include a determiningcircuit that determines the state of the lens barrier on the basis ofthe signal generated by the signal generating device. Further, the lensbarrier opening/closing mechanism may include a motor and the signalgenerating device could be a pulse generator, such as an encoder, thatoutputs predetermined pulses in response to a rotation of the motor.

In a particular case, the determining circuit determines that the lensbarrier opening/closing mechanism has operated normally if the pulsegenerator outputs a predetermined number of pulses during the operationof the lens barrier opening/closing mechanism.

If the zoom camera uses a lens barrier apparatus as described above andthe lens barrier opening/closing mechanism is arranged to drive the lensbarrier in a first direction to open the lens barrier and a seconddirection to close the lens barrier, a controller in the camera can beset such that, when the lens barrier is being driven in the firstdirection, if the determining circuit determines that the lens barrieropening/closing mechanism has not operated normally, the lens barrier isdriven in the second direction and then the first direction again.Similarly, when the lens barrier is being driven in the seconddirection, if the determining circuit determines that the lens barrieropening/closing mechanism has not operated normally, the lens barriercan be driven in the first direction and then the second directionagain.

In this way, operation of the lens barrier apparatus can be re-tried anumber of times, for example three times, to attempt to correct a faultyoperation.

According to another aspect, a zoom camera includes a lens that can bemoved between a housed position and a predetermined photo-ready range, alens barrier, a first detector that detects the movement of the lensbetween the housed position and the photo-ready range, a second detectorthat detects whether the lens barrier is in an open condition or in aclosed condition, and a controller that prevents the lens barrier frombeing closed unless the lens is at the housed position and prevents thelens from being moved from the housed position if the lens barrier isclosed. With this arrangement, the zoom camera cannot be operated forphotography unless the lens barrier is open.

According to yet another aspect, a compact camera includes a lensbarrier that can be opened and closed, a lens barrier driving mechanismto open and close the lens barrier, a motor connected to the lensbarrier driving mechanism for actuating the lens barrier drivingmechanism to drive the lens barrier, and an encoder which outputs apredetermined signal synchronously with operation of the motor.

Preferably, the compact camera further includes a controller whichjudges whether movement of the barrier has completed in accordance withthe predetermined signal generated by the encoder. Further, if thepredetermined signal is a pulse signal including a plurality of pulsesgenerated in response to operation of the motor, and the controllerincludes a counter which counts a number of the pulses carried by thepulse signal, the controller can determine that the movement of thebarrier is complete when the counter has reached a predetermined value.Also, the controller can determine that the movement of the barrier isincomplete if a pulse is not generated within a predetermined timeperiod and the counter has not reached the predetermined value.

Similar to the above, when the motor is driven in a predetermineddirection in order to drive the lens barrier, if the controllerdetermines that the movement is incomplete, the motor is driven in adirection opposite to the predetermined direction and then driven in thepredetermined direction again. In this way, the operation of the barrieris retried in order to attempt to correct a fault.

According to yet another aspect, a zoom compact camera includes a lensbarrier, a barrier driving mechanism, and a lens barrel housing aplurality of lens groups. The lens barrel may be movable in an opticalaxis direction within a predetermined movable range. The zoom compactcamera also includes a lens moving mechanism provided in the lens barrelto move at least one group of the plurality of lens groups with respectto the lens barrel, a motor for generating driving force, a drivingforce transmitting mechanism which transmits driving force generated bythe motor to one of the barrier driving mechanism and the lens movingmechanism through a first gear train and a second gear train,respectively, and a switching mechanism for selectively switchingbetween the first gear train and the second gear train. With thearrangement of this aspect, one motor is used to drive two distinctmechanisms, such that the size and complexity of the camera isminimized.

Preferably, the switching mechanism selectively switches according to aposition of the lens barrel within the movable range. In particular,where the movable range includes a zooming area and a housed positionwhich is outside of the zooming area, the barrier can be arranged suchthat it is opened and closed only when the lens is located at the housedposition by selecting the first gear train when the lens barrel islocated at the housed position and selecting the second gear train whenthe lens barrel is located within the zooming area.

According to a further aspect, a zoom compact camera includes a movablebarrel which is movable between a photo-ready range and a housedposition, a lens barrier provided at the front end of the moving lensbarrel, and a lens barrier mechanism, which opens and closes the lensbarrier. The zoom compact camera further includes a shutter unit housedin the moving lens barrel, a movable lens which is supported by theshutter unit in a manner enabling movement in the optical axisdirection, a motor which drives the movable lens and the lens barriermechanism, and a driving system switching mechanism which connects themotor to the movable lens, as the moving barrel moves from the housedposition to the photo-ready range and connects the motor to the lensbarrier mechanism as the moving lens barrel moves from the photo-readyrange to the housed position.

In the above arrangement, since the position of the moving lens barrelis used to determine which mechanism is driven, a separate controller orsensor is not needed in order to control the switching mechanism.

According to yet another aspect, a zoom compact camera is provided witha lens barrier opening/closing mechanism that includes at least tworotating barrier members, each of which rotates about a pivot, a drivering which is driven to rotate about the optical axis, and at least tworotation force transmitting links, each of which is supported on thedrive ring and is provided with an engaging part which engages with arespective one of the at least two rotating barrier members. Theengaging part of each of the at least two rotation force transmittinglinks is formed with a first section that non-resiliently moves the atleast two rotating barrier members in an opening direction when thedrive ring rotates from a position at which the barrier is fully closedto a position at which the barrier is opened immediately. The firstsection also resiliently urges the at least two rotating barrier memberstowards the closing direction by a spring force when the drive ringrotates from the position at which the barrier is opened intermediatelyto the position at which the barrier is fully closed. The engaging partincludes a second section that non-resiliently moves the pair ofrotating barrier members in the closing direction, when the drive ringrotates from the position at which the barrier is fully opened to theposition at which the barrier is opened intermediately and resilientlyurges the pair of rotating barrier members towards the opening directionby a spring force when the drive ring rotates from the position at whichthe barrier is opened intermediately to the position at which thebarrier is fully opened.

According to the arrangement of this aspect, at the beginning ofdriving, the lens barrier opening/closing mechanism is drivennon-resiliently in order to overcome any initial external forces thatmay prevent the barrier from opening or closing. For example, if asticky substance such as juice or the like is accidentally spilled onthe barrier, thereafter the driving of the barriers is resilient andthey are resiliently held at their final position such that, if anexternal force is applied, the barriers will not break. For example, ifa finger is placed between the barriers as they are closing or thebarriers are forced open from a closed position. Further, after theforce is removed, the barriers will resiliently spring-back to thecorrect position.

According to yet a further aspect, a zoom compact camera is providedwith a barrier mechanism that includes at least a pair of barrierblades, a first device for non-resiliently opening the barrier blades byat least a predetermined amount when the barrier blades are closed andto be opened, and a second device for resiliently and fully opening thebarrier blades such that the barrier blades are spring biased againstexternal forces. The zoom compact camera is provided with a third devicefor non-resiliently closing the barrier blades by at least apredetermined amount when the barrier blades are fully opened and to beclosed, and a fourth device for resiliently and completely closing thebarrier blades such that the barrier blades are spring biased againstexternal forces.

According to still yet another aspect, a zoom compact camera is providedwith a barrier mechanism that includes at least a pair of barrier bladeshaving a projection formed on each of the barrier blades, a drive ring,at least a pair of engaging members that have an engaging opening formedthereon where each of the engaging members are rotatably supported onthe drive ring, and a driving mechanism for driving the drive ring. Theprojection on each of the barrier blades is engaged with a correspondingone of the engaging openings, and when the drive rings is driven theengaging openings interact with the corresponding projections such thatduring one portion of the driving the projections are non-resilientlydriven and during another portion of the driving the projections areresiliently driven.

According to a further aspect, a camera is provided with a lens barrieropening/closing mechanism that includes at least one barrier memberwhich moves through a predetermined range, a drive element, at least onecoupling element that transmits a driving force of the drive element todrive the at least one barrier member, and a spring member having apredetermined resilient force. The spring member acts on the couplingelement only during a predetermined portion of the predetermined rangeof driving and decouples the transmission of the driving force in theevent that an external force greater than the resilient force is appliedto the barrier member.

According to a further aspect, a zoom compact camera is provided with abarrier mechanism, which opens and closes a camera aperture at the frontend of a camera lens barrel, and which includes a pair of rotatingbarrier members which open and close the camera aperture which arecentrally and rotatably supported on a pair of pivots that arepositioned substantially opposite each other with respect to the opticalaxis, and which are provided with a boss protrusion at a position thatis eccentric with respect to the pivot. The zoom compact camera isfurther provided with an opening/closing ring which is driven to rotateabout the optical axis, a pair of rotation force transmitting linkswhich are pivoted on the opening/closing ring, which are provided withan engaging part that engages with the boss protrusion of each rotatingbarrier member, and which open and close the pair of rotating barriermembers upon rotation of the opening/closing ring, a single springmember which is positioned on a part of the opening/closing ring at oneside of a line that joins the pair of pivots of the rotating barriermembers and rotationally urges the pair of rotation force transmittinglinks, and a sector gear part which is positioned on a part of theopening/closing ring at the other side of the line that joins the pairof pivots of the rotating barrier members and drives the opening/closingring to rotate.

In this aspect, because the components are minimized and appropriatelypositioned within the camera, the size of the camera can be minimized.

According to yet a further aspect, a camera includes a barriermechanism, which opens and closes a camera aperture at the front end ofa camera lens barrel. The barrier mechanism includes a drive ring, atleast one barrier member, at least one coupling element provided on thedrive ring that transmits a driving force of the drive element to drivethe barrier member, a spring member provided on the drive ring whichresiliently biases the coupling element in a predetermined manner, and amechanical connection part provided on the drive ring to receive adriving force to allow the drive ring to be driven. In particular, thespring member and the mechanical connection part are provided onportions of the drive ring that are opposite to each other in relationto the coupling element.

According to yet another aspect, a zoom compact camera is provided witha lens barrier apparatus that includes a lens barrier which is able tobe opened and closed and is provided on the front face of a lens barreland protects a camera lens, a motor which drives the opening/closing ofthe lens barrier, an encoder which outputs a predetermined signal inaccompaniment with the rotation of the motor, and a drive controller.When a battery is set in the camera, the drive controller drives themotor in the direction in which the lens barrier is closed, and when thepredetermined signal is not output from the encoder in the drivingprocess, the drive controller drives the motor in the direction in whichthe lens barrier is opened and then drives the motor in the direction inwhich the lens barrier is closed again.

With this arrangement, if the condition of the lens barrier is erasedfrom memory due to the replacement of the battery or the like, thecondition of the lens barrier can be determined without the need of anyadditional sensors or the like. Thus, the camera uses a minimal numberof components and its size is minimized.

According to yet another aspect, a lens barrier apparatus includes alens barrier that is movable between at least two states and that isprovided on the front face of a lens barrel to protect a camera lens, asensor that senses the state of the lens barrier, a motor that drivesthe lens barrier, and a drive controller. The drive controller operatessuch that, if, during driving of the lens barrier in a first direction,an intended state is not reached, the controller drives the motor in asecond direction opposite to the first direction for a predeterminedtime period and then drives the motor in the first direction again.

In a particular case, the sensor is a signal generating device thatoutputs a pulsed signal in association with the movement of the lensbarrier. Also in this case, the at least two states can be a pluralityof states that are indicated by pulses output by the signal generatingdevice.

With the arrangement of this aspect, the lens barrier is controlled suchthat if the lens barrier does not open or close correctly, the openingor closing operation will be retried after first driving in an oppositedirection in order to attempt to dislodge the obstacle or the like thathas caused the failure.

According to yet a further aspect, a zoom compact camera includes a lensbarrier, a barrier driving mechanism, a lens barrel housing a pluralityof lens groups and being movable in an optical axis direction within apredetermined movable range, and a lens moving mechanism provided in thelens barrel to move at least one group of the plurality of lens groupswith respect to the lens barrel. The zoom compact camera is furtherprovided with a motor for generating driving force, an encoder whichoutputs a predetermined signal synchronously with operation of themotor, a driving force transmitting mechanism which transmits drivingforce generated by the motor to one of the barrier driving mechanism andthe lens moving mechanism through a first gear train and a second geartrain, respectively, and a switching mechanism for selectively switchingbetween the first gear train and the second gear train.

This aspect has the advantages of driving two mechanisms with one motorand using an encoder to determine the condition of both mechanismswithout other sensors.

According to yet another aspect, a zoom compact camera includes a lensbarrier that can be opened and closed, a lens barrier driving mechanismto open and close the lens barrier, a motor for actuating the lensbarrier driving mechanism to drive the lens barrier, and an encoderwhich outputs a predetermined signal synchronously with operation of themotor. The zoom compact camera also includes a first device fornon-resiliently opening the barrier blades by at least a predeterminedamount when the barrier blades are closed and to be opened, a seconddevice for resiliently and fully opening the barrier blades such thatthe barrier blades are spring biased against external forces, a thirddevice for non-resiliently closing the barrier blades by at least apredetermined amount when the barrier blades are fully opened and to beclosed, and a fourth device for resiliently and completely closing thebarrier blades such that the barrier blades are spring biased againstexternal forces.

This aspect includes the advantages of using an encoder to monitor thedriving of the lens barrier and of driving the lens barrier bladesnon-resiliently and resiliently, as discussed above.

According to yet another aspect, a zoom compact camera includes a lensbarrier that includes a plurality of barrier blades, a barrier drivingmechanism, a lens barrel housing a plurality of lens groups and beingmovable in an optical axis direction within a predetermined movablerange, and a lens moving mechanism provided in the lens barrel to moveat least one group of the plurality of lens groups with respect to thelens barrel. The zoom compact camera also includes a motor forgenerating driving force, a driving force transmitting mechanism whichtransmits driving force generated by the motor to one of the barrierdriving mechanism and the lens moving mechanism through a first geartrain and a second gear train, respectively, and a switching mechanismfor selectively switching between the first gear train and the secondgear train. The barrier driving mechanism includes a first device fornon-resiliently opening the barrier blades by at least a predeterminedamount when the barrier blades are closed and to be opened, a seconddevice for resiliently and fully opening the barrier blades such thatthe barrier blades are spring biased against external forces, a thirddevice for non-resiliently closing the barrier blades by at least apredetermined amount when the barrier blades are fully opened and to beclosed, and a fourth device for resiliently and completely closing thebarrier blades such that the barrier blades are spring biased againstexternal forces.

This aspect includes the advantages of using a single motor to drive tomechanisms and of driving the lens barrier blades non-resiliently andresiliently, as described above.

According to yet another aspect, a zoom compact camera includes a lensbarrier that includes a plurality of barrier blades, a barrier drivingmechanism, a lens barrel housing a plurality of lens groups and beingmovable in an optical axis direction within a predetermined movablerange, a lens moving mechanism provided in the lens barrel to move atleast one group of the plurality of lens groups with respect to the lensbarrel, and a motor for generating driving force. The zoom compactcamera further includes an encoder which outputs a predetermined signalsynchronously with operation of the motor, a driving force transmittingmechanism which transmits driving force generated by the motor to one ofthe barrier driving mechanism and the lens moving mechanism through afirst gear train and a second gear train, respectively, and a switchingmechanism for selectively switching between the first gear train and thesecond gear train.

The barrier driving mechanism includes a first device fornon-resiliently opening the barrier blades by at least a predeterminedamount when the barrier blades are closed and to be opened, a seconddevice for resiliently and fully opening the barrier blades such thatthe barrier blades are spring biased against external forces, a thirddevice for non-resiliently closing the barrier blades by at least apredetermined amount when the barrier blades are fully opened and to beclosed, and a fourth device for resiliently and completely closing thebarrier blades such that the barrier blades are spring biased againstexternal forces.

This aspect includes the advantages of using an encoder to determine thecondition of the barrier blades, the use of a single motor to drive twomechanisms, and of driving the barrier blades non-resiliently andresiliently, as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described below in detail with reference to theaccompanying drawings, in which similar parts are indicated by likereference numerals throughout the drawings, and wherein:

FIG. 1 is a schematic view and a block diagram of an example of amechanical structure of a camera, to realize a method of focusing for azoom lens camera of the present embodiment;

FIG. 2 is a schematic view of a structure of an example of a zoom lenssystem according to the method of focusing of the present embodiment;

FIG. 3 is a graphic representation of an example of lens movementcontrol according to the method of focusing of the present embodiment;

FIG. 4 is a graphic representation of another example of lens movementcontrol according to the method of focusing of the present embodiment;

FIG. 5 is a graphic representation of another example of lens movementcontrol according to the method of focusing of the present embodiment;

FIG. 6 is a graphic representation of another example of lens movementcontrol according to the method of focusing of the present embodiment;

FIG. 7 is a graphic representation of another example of lens movementcontrol according to the method of focusing of the present embodiment;

FIG. 8 is an enlarged schematic perspective view which shows part of azoom lens barrel according to the present embodiment;

FIG. 9 is a schematic perspective view of the zoom lens barrel shown inFIG. 8, in a different condition;

FIG. 10 is an enlarged exploded perspective view of a part of the zoomlens barrel of the present embodiment;

FIG. 11 is a schematic perspective view illustrating a state where anAF/AE shutter unit of the zoom lens barrel is mounted to a first movingbarrel;

FIG. 12 is an exploded perspective view illustrating main parts of theAF/AE shutter unit of the zoom lens;

FIG. 13 is a schematic perspective view of an outline of a third movingbarrel of the zoom lens barrel;

FIG. 14 is a front elevational view of a fixed lens barrel block of thezoom lens barrel;

FIG. 15 is a sectional view of an upper part of the zoom lens barrel ofthe present invention in a most extended state;

FIG. 16 is a sectional view of an upper part of the zoom lens barrel,when in a housed state, illustrating essential parts;

FIG. 17 is a sectional view of an upper part of the zoom lens barrel,illustrating essential parts in a maximum extended state;

FIG. 18 is a sectional view of an upper part of the zoom lens barrel ina housed state;

FIG. 19 is an exploded perspective view of the overall structure of thezoom lens barrel;

FIG. 20 is a block diagram of a controlling system to control anoperation of the zoom lens barrel;

FIG. 21 is a sectional view illustrating a state when the zoom lensbarrel is positioned close to a "wide" end, and further a state before arelease button is released;

FIG. 22 is a sectional view illustrating a state when the zoom lensbarrel is positioned close to a "wide" end, and further a stateimmediately after the release button is released;

FIG. 23 is a sectional view illustrating a state when an external forcein the direction of the camera body is made to the front of the firstmoving barrel, and a whole lens barrel unit is retracted into the camerabody, and the a rear lens group collides with a film F;

FIG. 24 is a schematic view illustrating loci of movements of the frontlens group and the rear lens group;

FIG. 25 is a schematic view illustrating movements of the rear lensgroup with respect to the front lens group;

FIG. 26 is a front elevational view of an example of an embodiment of azoom lens camera according to the present invention;

FIG. 27 is a rear elevational view of the zoom lens camera shown in FIG.26;

FIG. 28 is a plan view of the zoom lens camera shown in FIG. 26;

FIG. 29 is a block diagram of the main parts of a control system of thezoom lens camera of the present embodiment;

FIG. 30 is a schematic view of a structure of a zoom code plate andbrushes, and a structure of detection of a position of a zoom code incontact with the brushes to detect a position of the lenses of the zoomlens camera;

FIG. 31 is a schematic view illustrating an example of an electroniccircuit to detect the zoom code, in contact with the brushes, as avoltage;

FIG. 32 is a table illustrating conversions of a voltage, obtainedthrough contact with the brushes, into a code;

FIG. 33 is a schematic view illustrating an example of an electroniccircuit of a strobe;

FIG. 34 is a schematic view illustrating movement of the front lensgroup and the rear lens group of the zoom lens camera;

FIG. 35 is a schematic view illustrating movement sequences of a wholeunit driving motor and a rear lens group driving motor during exposure(i.e., during focusing) of the zoom lens camera;

FIG. 36 is a schematic view illustrating movement sequences of the wholeunit driving motor and the rear lens group driving motor during lensreturn of the zoom lens camera;

FIG. 37 is an exploded perspective view of a peripheral structure of therear lens group of the zoom lens barrel;

FIG. 38 is a plan view of the main parts of an example of an initialposition detecting device of the rear lens group of the presentembodiment;

FIG. 39 is a sectional view of the initial position detecting device ofthe rear lens group, at a state when the rear lens group is at theinitial position;

FIG. 40 is a sectional view of the initial position detecting device ofthe rear lens group, at a state when the rear lens group is not at theinitial position;

FIG. 41 is a flow chart of a main process of the zoom lens camera;

FIG. 42 is a flow chart of a reset process of the zoom lens camera;

FIG. 43 is a flow chart of an AF lens initialization process of the zoomlens camera;

FIGS. 44 and 45 show a flow chart of a lens housing process of the zoomlens camera;

FIG. 46 is a flow chart of a lens extension process of the zoom lenscamera;

FIG. 47 is a flow chart of a zoom "tele" movement process of the zoomlens camera;

FIG. 48 is a flow chart of a zoom "wide" movement process of the zoomlens camera;

FIG. 49 is a flow chart of a photographing process of the zoom lenscamera;

FIG. 50 is a flow chart of a main charging process of the zoom lenscamera;

FIG. 51 is a flow chart of a shutter initialization process of the zoomlens camera;

FIG. 52 is a flow chart of a zoom code input process of the zoom lenscamera;

FIG. 53 is a flow chart of an AF pulse confirmation process of the zoomlens camera;

FIG. 54 is a flow chart of an AF return process of the zoom lens camera;

FIG. 55 is a flow chart of a barrier closing process of the zoom lenscamera;

FIG. 56 is a flow chart of a barrier opening process of the zoom lenscamera;

FIG. 57 is a flow chart of a zoom driving process of the zoom lenscamera;

FIG. 58 is a flow chart of an AF two-stage extension process of the zoomlens camera;

FIG. 59 is a flow chart of a zoom return process of the zoom lenscamera;

FIG. 60 is a flow chart of a zoom return process and a zoom standbyconfirmation process of the zoom lens camera;

FIG. 61 is a flow chart of a photographing charging process of the zoomlens camera;

FIG. 62 is a flow chart of a focusing process of the zoom lens camera;

FIGS. 63, 64 and 65 show a flow chart of an exposure process of the zoomlens camera;

FIG. 66 is a flow chart of a lens return process of the zoom lenscamera;

FIG. 67 is a flow chart of a lens driving operation process of the zoomlens camera;

FIG. 68 is a flow chart of a test function process of the zoom lenscamera;

FIG. 69 is a flow chart of an AF pulse counting process of the zoom lenscamera;

FIG. 70 is a flow chart of a zoom driving check process of the zoom lenscamera;

FIG. 71 is a flow chart of an AF driving process of the zoom lenscamera;

FIG. 72 is a flow chart of a zoom pulse counting process of the zoomlens camera;

FIG. 73 is a flow chart of an AF driving check process of the zoom lenscamera;

FIG. 74 is a schematic perspective view of a part of the zoom lensbarrel;

FIG. 75 is a front elevational view of the part shown in FIG. 74;

FIG. 76 is a front elevational view of the part shown in FIG. 74, in adifferent state from the state of FIG. 75;

FIG. 77 is a plan view of positions of switching cams in a photographingstate;

FIG. 78 is a plan view of positions of switching cams in a housed state;

FIG. 79 is an enlarged exploded perspective view of a part of the zoomlens barrel;

FIG. 80 is an enlarged perspective view of a switching cam, a rotationswitching member and a planetary gear;

FIG. 81 is an enlarged perspective view of the switching cam, therotation switching member and the planetary gear, in a different statefrom the state shown in FIG. 80;

FIG. 82 is an enlarged perspective view of the switching cam, therotation switching member and the planetary gear, in yet a differentstate from the states shown in FIGS. 80 and 81;

FIG. 83 is a schematic perspective view illustrating outlines of theAF/AE shutter unit and a linear guide member in a photographing state;

FIG. 84 is a schematic perspective view illustrating outlines of theAF/AE shutter unit and the linear guide member in a housed state;

FIG. 85 is a schematic perspective view illustrating an outline of theAF/AE shutter unit shown in FIG. 83;

FIG. 86 is a schematic perspective view illustrating an outline of theAF/AE shutter unit shown in FIG. 84;

FIG. 87 is a sectional view or an upper part of the zoom lens barrel,illustrating the main parts of a lens barrier apparatus;

FIG. 88 is an exploded perspective view of the lens barrier apparatus ofthe zoom lens barrel;

FIG. 89 is a front elevational view of the lens barrier apparatus of thepresent embodiment, illustrating forced opening sections while mainbarrier blades are driver to be opened from a closed state;

FIG. 90 is a front elevational view of the lens barrier apparatus,illustrating forced opening sections while main barrier blades aredriven to be opened from a closed state;

FIG. 91 is a front elevational view of the lens barrier apparatus,illustrating forced opening sections while main barrier blades aredriven to be closed from an opened state;

FIG. 92 is a front elevational view of the lens barrier apparatus,illustrating forced opening sections while main barrier blades aredriven to be closed from an opened state;

FIG. 93 is a plan view of the lens barrier apparatus provided at thefront of the first moving barrel;

FIG. 94 is a front elevational view of the lens barrier apparatus of thepresent invention when the main barrier blades are driven by force to beclosed from an open state;

FIG. 95 is a front elevational view of the lens barrier apparatus of thepresent invention when the main barrier blades are driven by force to beopened from a closed state;

FIG. 96 is a front schematic view of the forces acting on a barrierdriving lever for the process in which the main barrier blades areopened from the closed condition; and

FIG. 97 is a front schematic view of the forces acting on the barrierdriving lever for the process in which the main barrier blades areclosed from the opened condition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described with reference to theattached drawings.

FIG. 1 is an (essentially) schematic representation of various elementswhich comprise a zoom lens camera according to the present invention.More specific details of such a camera are described hereinafter withreference to FIGS. 8-103. Thus, although they may describe similarand/or identical parts, the reference numerals used in FIG. 1 are notidentical to those used in the other figures.

As shown in FIG. 1, a zoom lens barrel 410 is provided with a front lensgroup L1 of positive power and a rear lens group L2 of negative powershown in FIG. 1. On an outer periphery of a stationary ring 411, adriving ring 412 is rotatively supported, and on an inner peripherythereof, a front lens group supporting ring 413, which supports thefront lens group L1, and a rear lens group supporting ring 414, whichsupports the rear lens group L2, are engaged. On the stationary ring411, a linear guide groove 411a is formed parallel to an optical axis OAof the zoom lens barrel 410, and a radial pin 415, provided on the frontlens group supporting ring 413, is engaged with a lead groove 412aformed on an inner peripheral surface of the driving ring 412. Theradial pin 415 passes through the linear guide groove 411a to engagewith the lead groove 412a. On an outer periphery of the driving ring412, a gear 417 is fixedly engaged with a gear 419 of a whole unitdriving (whole unit moving) motor 418.

On the stationary ring 411, a linear guide groove 411b is formedparallel to the optical axis of the zoom lens barrel 410. A radial pin420, provided on the rear lens group supporting ring 414, engages withthe linear guide groove 411b. On the front lens group supporting ring413, a rear lens group driving (rear lens group moving) motor 421 and adriving screw 422 driven rotatively by the rear lens group driving motor421, are provided. The driving screw 422 engages with an anti-rotatingnut 423 provided on the rear lens group supporting ring 414.

In the above described structural arrangement, when the driving ring 412is rotatively driven by the whole unit driving motor 418, in accordancewith the relationship between the lead groove 412a and the linear guidegroove 411a, the front lens group supporting ring 413 (i.e., the frontlens group L1) moves in the optical axis direction. Since the rear lensgroup supporting ring 414 (i.e., the rear lens group L2) is secured tothe front lens group supporting ring 413 through the driving screw 422and the nut 423, the rear lens group supporting ring 414 moves togetherwith the front lens group supporting ring 413 in the optical axisdirection. Thus it can be understood that the whole unit driving motor418 moves both lens groups, i.e., the front and rear lens groups,together as a whole.

On the other hand, when the driving screw 422 is rotatively driven bythe rear lens group driving motor 421, the rear lens group supportingring 414 (i.e., the rear lens group L2) moves relatively to the frontlens group supporting ring 413 (i.e., the front lens group L1). Thus itcan be understood that the rear lens group driving motor 421 is a motorwhich varies the distance between the rear lens group L2 and the frontlens group L1.

The whole unit driving motor 418 and the rear lens group driving motor421 are respectively controlled and driven by respective motorcontrolling circuits 425 and 426. The whole unit driving motor 418 isalso connected to a zoom finder 427 so that a field of view of thefinder varies when the whole unit driving motor 418 is actuated.

In the main body of the camera, a zoom operating device 431, a focusoperating device 432, an object distance measuring device 433 and aphotometering apparatus 434 are provided. The zoom operating device 431provides a zooming command, namely commands to move from a "wide"position to a "tele" position, or vice versa, to the zoom lens barrel410, i.e., the front lens group L1 and the rear lens group L2. The zoomoperating device 431 consists of, for example, a switch according to amomentary mechanical system. The focus operating device 432 consists of,for example, of a release button. When the focus operating device 432 isdepressed by a half-depression (half-step), object distance measurementinformation is input to the object distance measuring device 433 andphotometering information is input to the photometering apparatus 434.When the focus operating device 432 is fully depressed (full step), thefocusing operation commences, and a shutter 436, mounted to the frontlens group supporting ring 413, is operated via a AE motor controllingcircuit 435. The shutter 436 opens a shutter blade 436a for apredetermined time according to the photometering information outputfrom the photometering apparatus 434.

In the zoom lens camera as above described, when the zoom operatingdevice 431 is operated, the whole unit driving motor 418 is driven viaat least the motor controlling circuit 425, and the front lens group L1and the rear lens group L2 are moved as a whole. The rear lens groupdriving motor 421 may also be driven via the motor controlling circuit426. With the above structural arrangement, it should be understood thatthe movement of the front lens group L1 and the rear lens group L2 bythe zoom operating device 431 is not operated under the conventionalconcept of zooming in which the focal point does not move. When the zoomoperating device 431 is operated, the following two modes are available,namely:

1. A mode to move the front lens group L1 and the rear lens group L2 inthe optical axis direction, without varying the distance therebetween,by driving only the whole unit driving motor 418; and,

2. A mode to move the front lens group L1 and the rear lens group L2 inthe optical axis direction, while varying the distance therebetween, bydriving both the whole unit driving motor 418 and the rear lens groupdriving motor 421.

In mode 1, during the zooming operation it is impossible to focus on thesubject. However, this is not a problem in a lens-shutter type camera,since the image is not observed through the photographing opticalsystem, and it is sufficient that the subject is only focused when theshutter is released. In mode 2, during the zooming operation, the frontlens group L1 and the rear lens group L2 are moved without considerationof whether the focal point moves, and when the shutter is released,focusing (focus adjusting) is carried out by moving both the whole unitdriving motor 418 and the rear lens group driving motor 421.

On the other hand, when the whole unit driving motor 418 is actuated bythe zoom operating device 431, the zoom finder 427 is driven so that thefinder field of view thereof is changed in accordance with the focallength set. Specifically, as the set focal length changes from a shortfocal length to a longer focal length, the finder field of view (angle)changes from a wider field of view to a narrower field of view. Thefinder field of view of course corresponds to a photographing imagesize. This kind of zoom finder is well known and is therefore not shown.

In the present invention, as mentioned above, when the zoom operatingdevice 431 is operated to set a focal length, the finder field of view(photographing image area) at the set focal length is observed throughthe zoom finder 427.

Further when the focus operating device 432 is operated in at least onepart of the focal length range set by the zoom operating device 431, thewhole unit driving motor 418 and the rear lens group driving motor 421are driven and subject focusing is performed. The movement of the frontlens group L1 and the rear lens group L2 by the whole unit driving motor418 and the rear lens group driving motor 421 is determined, not onlybased on subject distance information provided from the object distancemeasuring device 433, but also in accordance with focal lengthinformation set by the zoom operating device 431. In such a manner, whenthe focus operating device 432 is operated, by moving both the wholeunit driving motor 418 and the rear lens group driving motor 421, theposition of the lenses can be flexibly controlled, i.e., the position ofthe lenses has a degree of flexibility.

In theory, during an operation of the zoom operating device 431, themagnification of the finder and the focal length information are onlyvaried without driving the whole unit driving motor 418 or the rear lensgroup driving motor 421. When the focus operating device 432 isoperated, both the whole unit driving motor 418 and the rear lens groupdriving motor 421 are moved simultaneously according to the focal lengthinformation and the subject distance information obtained by the objectdistance measuring device 433 to move the front lens group L1 and therear lens group L2 to positions determined according to the focal lengthand the subject distance information.

The following discussion will illustrate several examples of a frontlens group L1, a rear lens group L2, and a controlling of movementthereof. Table 1 shows lens data regarding the front lens group L1 andthe rear lens group L2, and FIG. 2 is a drawing showing the structure ofthe lens groups. The lens data only shows a concrete example of theoptical system which is applicable to a two-lens group type zoom lensaccording to the present invention. The front lens group L1 consists offour lens groups having five lens elements, and the rear lens group L2consists of two lens groups having two lens elements (duplet).

In the following tables and the drawings (FIGS. 3 through 7), FNOrepresents the F number, f represents the focal length, ω represents thehalf angle of view, fB represents the back focal distance, ri representsthe curvature of radius of each lens surface, di represents thethickness of a lens or the distance between lenses, n represents therefractive index of the d-line, and ν represents the Abbe number.

                  TABLE 1                                                         ______________________________________                                                    FNO = 1:3.9-10                                                                F = 39-102 (mm)                                                               ω = 28.4°-12.0°                                           B = 9.47-63.1 (mm)                                                Surface No.                                                                             ri        di         n     ν                                     ______________________________________                                        1         20.550    2.10       1.48749                                                                             70.2                                     2         42.627    1.65       --    --                                       3         -15.428   1.66       1.83400                                                                             37.2                                     4         -30.458   3.06       --    --                                       5         631.122   2.80       1.51633                                                                             64.1                                     6         -16.980   0.10       --    --                                       7         91.952    3.42       1.53996                                                                             59.5                                     8         -11.244   1.60       1.80400                                                                             46.6                                     9         -23.784   12.56-2.59 --    --                                       10*       -42.469   2.50       1.58547                                                                             29.9                                     11        -26.490   5.04       --    --                                       12        -10.416   1.50       1.71299                                                                             53.9                                     13        -48.829   --         --    --                                       ______________________________________                                         *denotes an aspherical surface having rotational symmetry                     Aspherical Surface Data:                                                      K = 0.0, A4 = 5.96223 10.sup.-5, A6 = 2.52645 10.sup.-7, A8 = 2.89629         10.sup.-9                                                                

The shape of the aspherical surface having rotational symmetry can begenerally expressed as follows:

    x=Ch.sup.2 /{1+[1-(1+K)C.sup.2 h.sup.2 ].sup.1/2 }+A4h.sup.4 +A6h.sup.6 +A8h.sup.8 +A10h.sup.10 + . . .

wherein, h represents a height above the axis,

x represents a distance from a tangent plane of an aspherical vertex,

C represents a curvature of the aspherical vertex(1/r),

K represents a conic constant,

A4 represents a fourth-order aspherical factor,

A6 represents a sixth-order aspherical factor,

A8 represents an eighth-order aspherical factor,

A10 represents a tenth-order aspherical factor.

Data regarding zooming is shown in Table 2. In Table 2, TL representsthe distance from the primary surface to the image surface, D_(1G-2G)represents the distance between the front lens group L1 and the rearlens group L2. The values of TL and d_(1G-2G) represent absolutepositions of the first lens group L1 and the second lens group L2 whenzooming while keeping the in-focus condition with respect to an objectat infinite distance, and the lens positions are realized by a cammechanism in a conventional zoom compact camera. Specifically, uponsetting a focal length by a zoom switch, the first lens group L1 and thesecond lens group L2 move to positions defined in Table 2 which aredetermined by the focal length set.

However, according to the zoom lens camera of the present invention,upon setting a focal length by the zoom operating device 431, the firstlens group L1 and the second lens group L2 do not move to positionsdefined in Table 2.

In Table 2, XA (f) represents the total movement distance of the firstlens group L1 and the second lens group. L2 at a respective focal lengthby the whole unit moving motor 418 from reference positions thereof. Thereference positions (XA(f)=0) are defined by the positions of the lensgroups L1 and L2 when the lens groups are located at the shortest focallength (39 mm) while focusing on an object at infinity.

In Table 2, XB(f) represents the total movement distance of the secondlens group L2 with respect to the first lens group L1 at a respectivefocal length by the relative moving motor 421 from a reference positionof the rear lens group L2. The reference position (XB(f)=0) is definedas the position of the second lens group L2 when the lens groups L1, L2are located at the longest focal length (102 mm) while focusing on anobject at infinity.

The point is that the movement distances XA(f) and XB(f) are not givenjust by setting a focal length, but are given when the focus operatingdevice 432 is operated. Note that "0" in XA(f) and XB(f) representsreference positions and does not refer to stand-by positions of the lensgroups L1, L2 before the motors 418 and 421 are actuated. In otherwords, "0" in XA(f) and XB(f) does not mean that the motors 418 and 421are not driven when the focus operating device is operated.Mechanically, to realize a precise position control of the lens groups,it is preferred that the lens groups are positioned at waiting positionswhich are represented by negative values (positions moved in directionsopposite from the reference position) in Table 2 and are moved topositions shown in Table 2 upon operation of the focus operating devicefrom the waiting positions.

                  TABLE 2                                                         ______________________________________                                        f        TL     d.sub.1G-2G XA (f)                                                                              XB (f)                                      ______________________________________                                        39       47.45  12.56       0     9.97                                        45       50.36  10.44       2.91  7.85                                        70       66.66  5.42        19.21 2.83                                        95       85.56  3.05        38.11 0.46                                        102      91.11  2.59        43.66 0                                           ______________________________________                                    

As described above, in the zoom lens camera according to the presentinvention, the first lens group L1 and the second lens group L2 move topositions determined by set focal length information and detected objectdistance information by actuating the motors 418 and 421 using the zoomoperating device 431 and the focus operating device 432. Accordingly, itis possible to make zooming control and focusing control without usingthe cam mechanism by storing lens position data, consisting of acombination of stepped focal length information and stepped objectdistance information, in a memory, and digitally controlling the motors418 and 421 in accordance with the stored lens position data. Therefore,how to control the motors 418 and 421 in accordance with the informationin combination with the set focal length information and the detectedobject distance information is not within the scope of the main subjectof the present invention. The following discussion illustrates fiveadvantageous examples of how to control the motors 418 and 421 (lensgroups L1 and L2). It is possible to selectively employ these controlsin accordance with the zoom lens of the present invention.

In the following examples XA represents movement due to the whole unitdriving motor, XB represents movement due to the rear lens group drivingmotor, (f) represents the function of the focal length, (u) representsthe function of the subject distance, and ΔXA and ΔXB respectivelyrepresent movement during focusing due to the whole unit driving motorand the rear lens group driving motor. Namely, XAmax represents themaximum movement during zooming and additional focusing due to the wholeunit driving motor, XA(f)max represents the maximum movement duringzooming due to the whole unit driving motor, ΔXF(u) represents themovement based only on subject distance regardless of the focal length,XBmax represents the maximum movement during zooming and additionalfocusing due to the rear lens group driving motor, and XB(f)maxrepresents the maximum movement during zooming due to the rear lensgroup driving motor.

EXAMPLE 1

FIG. 3 is a first example of a front lens group L1 and a rear lens groupL2. In FIGS. 3 through 7, the length of the arrows of ΔXA and ΔXB areexaggeratedly drawn compared with the arrows of XA and XB.

In the present example, throughout the whole focal length range, set bythe zoom operating device 431, the total movement XA and the relativemovement of the rear lens group XB are given by the followingrelationships:

    XA=XA(f)+ΔXF(u)

    XB=XB(f)+ΔXF(u)

In other words, XA and XB are defined by the addition of a similarquantity of ΔXF(u), without having any relationship to the focal length.When the same amount of ΔXF(u) is added to XA and XB, in regard to thefunction of the subject distance (u), the distance of the rear lensgroup L2 from the image surface does not vary. The position of the rearlens group L2 indicated by the broken line (two-dotted) represents itsposition without an operation of the rear lens group driving motor.

In the present example, if the shortest subject distance u=700 mm, whenf=39 mm, then ΔXF(u)=1.17, and as f increases, the value of ΔXF(u) willincrease slightly, but when f=102 mm, then ΔXF(u)=1.25 and therefore theamount of increase is very little. Considering the depth of focus, it ispossible to control the movement (i.e., the movement of the lenses tothe desired position) of the lenses only by the subject distanceinformation, regardless of the focal length information from the zoomoperation device 431.

In the present example, the following relationships are given:

    XAmax=XA(f)max+ΔXF(u)max

    XBmax=XB(f)max+ΔXF(u)max

EXAMPLE 2

FIG. 4 shows a second example of a front lens group L1 and a rear lensgroup L2.

In the present example, around the short focal length end, set by thezoom operating device 431, the following relationships are defined:

    XA=XA(f)+ΔXA(u)

    XB=XB(f)+0

(i.e., regarding subject distance, the rear lens group L2 should notmove relative to the front lens group L1)

At other focal lengths, the following relationships are defined:

    XA=XA(f)+ΔXF(u)

    XB=XB(f)+ΔXF(u)

In the present example, if the shortest subject distance u=700 mm, whenf=39 mm, then ΔXA(u)=1.72. Regarding other focal lengths, the values ofΔXF(u) are approximately determined as follows:

when f=45 mm, then ΔXF(u)=1.17;

when f=70 mm, then ΔXF(u)=1.20;

when f=95 mm, then ΔXF(u)=1.24; and,

when f=102 mm, then ΔXF(u)=1.25.

Therefore, at focal lengths other than around the short focal lengthend, it is possible to control the position of the lenses only by thesubject distance information, regardless of the focal lengthinformation.

In the present example, the following relationships are defined:

    XAmax=XA(f)max+ΔXF(u)max

    XBmax=XB(f)max

Therefore, the relative movement of the rear lens group can beminimized. In this example, XB(f)max is less than XB(f)max in Example 1.

EXAMPLE 3

FIG. 5 shows a third example of a front lens group L1 and a rear lensgroup L2.

In the present example, around the long focal length end, set by thezoom operating device 431, the following relationships are defined:

    XA=XA(f)+0

(i.e., regarding subject distance, the front lens group L1 should notmove)

    XB=XB(f)+ΔXB(u)

At other focal lengths, the following relationships are defined:

    XA=XA(f)+ΔXF(u)

    XB=XB(f)+ΔXF(u)

In the present example, if the shortest subject distance u=700 mm, thevalues of ΔXF(u) are approximately determined as follows:

when f=39 mm, then ΔXF(u)=1.17;

when f=45 mm, then ΔXF(u)=1.17;

when f=70 mm, then ΔXF(u)=1.20; and,

when f=95 mm, then ΔXF(u)=1.24.

However, when f=102 mm, then ΔXB(u)=1.35.

Therefore, at focal lengths other than around the long focal length end,it is possible to control the position of the lenses only by the subjectdistance information, regardless of the focal length information.

In the present example, the following relationships are defined:

    XAmax=XA(f)max

    XBmax=XB(f)max+ΔXB(u)max

Therefore, the total movement by the whole unit driving motor isminimized.

EXAMPLE 4

FIG. 6 shows a fourth example of a front lens group L1 and a rear lensgroup L2.

In the present example, around the short focal length end, set by thezoom operating device 431, the following relationships are defined:

    XA=XA(f)+ΔXA(u)

    XB=XB(f)+0

(i.e., regarding subject distance, the rear lens group L2 should notmove relative to the front lens group L1)

Around the long focal length end, set by the zoom operating device 431,the following relationships are defined:

    XA=XA(f)+0

(i.e., regarding subject distance, the front lens group L1 should notmove)

    XB=XB(f)+ΔXB(u)

And at other focal lengths, the following relationships are defined:

    XA=XA(f)+ΔXF(u)

    XB=XB(f)+ΔXF(u)

In the present example, if the shortest subject distance u=700 mm, theposition of the lenses, other than at around the short or long focallength ends, are approximately determined as follows:

when f=39 mm, then ΔXA(u)=1.72;

when f=45 mm, then ΔXF(u)=1.17;

when f=70 mm, then ΔXF(u)=1.20;

when f=95 mm, then ΔXF(u)=1.24; and,

when f=102 mm, then ΔXB(u)=1.35.

Therefore, at focal lengths other than around the short or long focallength ends, it is possible to control the position of the lenses onlyby the subject distance information, regardless of the focal lengthinformation.

In the present example, the following relationships are defined:

    XAmax=XA(f)max

    XBmax=XB(f)max

Therefore, the movement of both lens groups is minimized, as well as therelative movement of the rear lens group.

EXAMPLE 5

FIG. 7 shows a fifth example of a front lens group L1 and a rear lensgroup L2.

In the present example, around the short focal length end, set by thezoom operating device 431, the following relationships are defined:

    XA=XA(f)+ΔXA(u)

    XB=XB(f)+0

(i.e., regarding subject distance, the rear lens group L2 should notmove against the front lens group L1)

At other focal lengths, the following relationships are defined:

    XA=XA(f)+0

(i.e., regarding subject distance, the front lens group L1 should notmove)

    XB=XB(f)+ΔXB(f,u)

In the present example, if the shortest subject distance u=700 mm, theposition of the lenses around the long focal length end is approximatelydetermined as follows:s

when f=39 mm, then ΔXA(u)=1.72;

when f=45 mm, then ΔXF(u)=1.90;

when f=70 mm, then ΔXF(u)=1.42;

when f=95 mm, then ΔXF(u)=1.35; and,

when f=102 mm, then ΔXB(u)=1.35.

Therefore, at the short focal length end, it is possible to control theposition of the lenses only by the subject distance information, and atother focal lengths it is possible to control the position of the lensesby the focal length information and the subject distance information.

In the present example, the following relationships are defined:

    XAmax=XA(f)max

    XBmax=XB(f)max

Therefore, the movement of both lens groups is minimized, as well as therelative movement of the rear lens group. The position of the lenses,however, may differ according to the focal length.

The mechanical structure of the zoom lens shown in FIG. 1 illustrates asimple example thereof. Various mechanical structures may actually bemade, and thus the present invention shall not refer to the mechanicalstructure itself.

As above described, according to the method of focusing the zoom lenscamera in the present invention, when the focus operating device isoperated, focusing is performed in such a manner that, the whole unitdriving motor which drives the front and the rear lens group as a whole,and the rear lens group driving motor which varies the distance betweenthe front lens group and the rear lens group, move together, and therebyflexible control of the lens position will be facilitated.

To realize the zoom lens and the method of lens driving shown in FIGS. 2through 7, several embodiments of the present invention will now bedescribed with reference to FIGS. 8 to 23.

The following embodiments of the present invention are applied to a lensshutter type of zoom lens camera, as shown in FIG. 26. The concept ofthe present zoom lens camera will now be described with reference toFIG. 20.

FIG. 20 shows a zoom lens barrel 10, provided in the present zoom lenscamera, of a three-stage delivery type having three moving barrels,namely a first moving barrel 20, a second moving barrel 19 and a thirdmoving barrel 16. Two lens groups are provided, namely a front lensgroup L1 having positive power and a rear lens group L2 having negativepower.

In the main body of the camera, a whole unit driving motor controllingcircuit 60, a rear lens group driving motor controlling circuit 61, azoom operating device 62, a focus operating device 63, a object distancemeasuring apparatus 64, a photometering system 65, an AE (i.e.,automatic exposure) motor controlling circuit 66, and a CPU (i.e.,central processing unit) 210, are provided. The CPU 210 controls theabove devices, circuits or apparati. Although the specific objectdistance measuring apparatus 64 which is used to provide informationregarding the object-to-camera distance does not form part of thepresent invention, one such suitable system is disclosed in commonlyassigned U.S. patent application Ser. No. 08/605,759, filed on Feb. 22,1996, the entire disclosure of which is expressly incorporated byreference herein. Although the systems disclosed in such application areof the so-called "passive" type, other known autofocus systems (e.g.,active rangefinding systems such as those based on infrared light andtriangulation) may be used. Similarly, a photometering system asdisclosed in the noted U.S. patent application Ser. No. 08/605,759 couldbe implemented as photometering system 65.

When the zoom operating device 62, for example in the form of a zoomlever provided on the camera body (i.e., a "wide" zoom button 62WB and a"tele" zoom button 62TB, as shown in FIG. 28), is operated, the CPU 210outputs commands to the whole unit driving motor controlling circuit 60to move the front lens group L1 and the rear lens group L2, rearwardlyor forwardly without consideration of the focal length and a focal pointthereof.

In the following explanation, forward and rearward movements of thelenses L1 and L2 by the whole unit driving motor control circuit 60 (themotor 25) are referred to as the movement toward "tele" and the movementtoward "wide", respectively, since forward and rearward movements of thelenses L1 and L2 occur when the zoom operating device 62 is operated to"tele" and "wide" positions.

The image magnification of the visual field of the finder 427 (FIG. 1),varies sequentially to the variation of the focal length through theoperation of the zoom operating device 62. Therefore, the photographermay perceive the variation of the set focal length through the operationof the zoom operating device 62, by observing the variation of imagemagnification of the visual field of the finder. In addition, the focallength, as set by the operation of the zoom operating device 62, may beindicated by a value displayed on an LCD (i.e., liquid crystal display)panel 224, as shown in FIG. 28.

When the focus operating device 63 is operated, the CPU 210 drives thewhole unit driving motor 25, driven via the whole unit driving motorcontrolling device 60, and additionally drives a rear lens group drivingmotor 30, driven via the rear lens group driving motor controllingcircuit 61, so that the front and rear lens groups L1 and L2 are movedto a position corresponding to a set focal length and a detected objectdistance, and whereby the zoom lens is focused on the subject.

Specifically, the focus operating device 63 is provided with a releasebutton 217B. A photometering switch SWS and a release switch SWB aresynchronized with the release button 217B. When the release button 217Bis half-depressed (half step), through the CPU 210, the photometeringswitch SWS is turned ON, and the respective object distance measuringand photometering commands are input to the object distance measuringapparatus 64 and the photometering apparatus 65.

When the release button 217B is fully depressed (full step), the CPU 210causes the release switch SWR to be turned ON, and according to theresult of the object distance measuring device and a set focal length,the whole unit driving motor 25 and the rear lens group driving motor 30are driven. Thus, the focusing process, in which the front lens group L1and the rear lens group L2 move to the focusing position, is executed.Further, an AE motor 29 of an AF/AE (i.e., autofocus/autoexposure)shutter unit 21 (FIG. 21) is driven via the AE motor controlling circuit66, and a shutter 27 is actuated. During the shutter action, upon theinput of the photometering information output from the photometeringapparatus 65, the CPU 210 drives the AE motor 29 and opens shutterblades 27a of the shutter 27 for a specified period of time. In the zoomlens camera of the present embodiment, immediately after the shutterblades 27a are closed, by driving the rear lens group driving motor 30,the rear lens group L2 moves forwardly to the initial position thereof.The focus operating device 63, though not shown, includes switchingmechanism to execute the focusing process by the CPU 210.

When the zoom operating device 62 is operated, the CPU 210 drives thewhole unit driving motor 25, and the front lens group L1 and the rearlens group L2 move together as a whole in the optical axis direction.Simultaneous with such a movement, the rear lens group driving motor 30may also be driven via the rear lens group driving motor controllingcircuit 61. However, this operation is not performed under theconventional concept of zooming in which the focal length is variedsequentially without moving the position of the focal point.

Motors 29 and 30 are identical, and comprise DC motors having a minimumtorque of 1.5 gram*cm at a rated voltage (i.e., 1.5V); motor 25comprises a DC motor which has a minimum torque of 12.0 gram*cm at arated voltage (i.e., 2.4V). One example of motors 29 and 30 are motorsmanufactured by Sanyo Seimitsu Co., Ltd. of Japan, under motor code No.M-01166600; and an example of motor 25 is a motor which is alsomanufactured by Sanyo Seimitsu Co., Ltd. of Japan, under motor code No.M-01154200.

An example of the embodiment of the zoom lens barrel according to theabove concept will now be described with reference to FIGS. 18 and 19.

The overall structure of the zoom lens barrel 10 in the presentinvention will firstly be described. The zoom lens barrel 10 is providedwith the first moving barrel 20, the second moving barrel 19, the thirdmoving barrel 16, and a fixed lens barrel block 12. The third movingbarrel 16 is engaged with a cylindrical part of the fixed lens barrelblock 12, and moves in the optical axis direction upon being rotated.The third moving barrel 16 is provided on an inner periphery thereofwith a linear guide barrel 17, which is restricted in rotation. Thelinear guide barrel 17 and the third moving barrel 16 move together as awhole in the optical axis direction, with the third moving barrel 16rotating relative to the linear guide barrel 17. The first moving barrel20 moves in the optical axis direction with rotation thereof beingrestricted. The second moving barrel 19 moves in the optical axisdirection, while rotating relative to the linear guide barrel 17 and thefirst moving barrel 20. The whole unit driving motor 25 is secured tothe fixed lens barrel block 12. A shutter mounting stage 40, on whichthe AE motor 29 and the rear lens group driving motor 30 are mounted, issecured to the first moving barrel 20. The front lens group L1 and therear lens group L2 are respectively supported by a lens supportingbarrel 34 and a lens supporting barrel 50.

On the inner periphery of the fixed lens barrel block 12, a femalehelicoid 12a, and a plurality of linear guide grooves 12b formedparallel to an optical axis O, are provided. An aperture plate 14 havingan aperture 14a which defines a portion of the film to be exposed, isprovided, as shown in FIG. 18.

In the fixed lens barrel block 12, a gear housing 12c, expanding in theradial direction, and extending in the optical axis direction, isprovided as shown in FIG. 14. In the gear housing 12c, a driving pinion15, extending in the optical axis direction, is rotatively held. Theends of a shaft 7 of the driving pinion 15 are rotatively supported, bya supporting hollow 4 provided in the fixed lens barrel block 12, and bya supporting hollow 31a provided on a gear supporting plate 31,respectively. The teeth of the driving pinion 15 project into the innerperiphery of the fixed lens barrel block 12.

At the bottom part of one of the linear guide grooves 12b, namely 12b',the code plate 13a having a predetermined pattern is fixed, as shown inFIG. 14. The linear guide groove 12b' is provided so that it may bepositioned at an approximate diagonal position of the photographingplane in regard to the fixed lens barrel block 12. The code plate 13a isprovided along substantially the whole of the length of the fixed lensbarrel block 12 (i.e., in the optical axis direction). The code plate13a is part of a flexible printed circuit board 13 positioned outsidethe fixed lens barrel block 12. On the flexible printed circuit board13, a photointerrupter 1 is secured, which in combination with arotating plate 2, comprises an encoder for detecting a rotation of thewhole unit driving motor 25. The rotating plate 2 is fixed on a shaft ofthe whole unit driving motor 25 as shown in FIG. 19.

On an inner periphery of the third moving barrel 16, a plurality oflinear guide grooves 16c, formed parallel to the optical axis, areprovided. At an outer periphery of the rear end of the third movingbarrel 16, a male helicoid 16a, which engages with the female helicoid12a of the fixed lens barrel block 12, and an outer peripheral gear 16b,which engages with the driving pinion 15, are provided as shown in FIG.13. The driving pinion 15 has an axial length sufficient to be capableof engaging with the outer peripheral gear 16b throughout the entirerange of movement of the third moving barrel 16 in the optical axisdirection.

The linear guide barrel 17 is provided, on a rear part of an outerperiphery thereof, with a rear end flange 17d. The rear end flange 17dhas a plurality of engaging projections 17c projecting away from theoptical axis in the radial direction. An anti-dropping flange 17e isprovided just in front of the rear end flange 17d. The anti-droppingflange 17e has a radius smaller than the rear end flange 17d. In thecircumferential direction of the anti-dropping flange 17e, a pluralityof notches 17f are formed. On an inner periphery of the rear end of thethird moving barrel 16, a plurality of engaging projections 16d,projecting towards the optical axis in a radial direction are provided,as shown in FIG. 18. By inserting the engaging projections 16d into thenotches 17f, the engaging projections 16d are positioned between theflanges 17d and 17e, and by the relative rotation of the linear guidebarrel 17, the engaging projections 16d are engaged with the linearguide barrel 17. On the rear end surface of the linear guide barrel 17,an aperture plate 23 having an aperture 23a approximately the same shapeas the aperture 14a, is fixed.

The relative rotation of the linear guide barrel 17, with respect to thefixed lens barrel block 12, is restricted by the slidable engagement ofthe plurality of engaging projections 17c with the corresponding linearguide grooves 12b, formed parallel to the optical axis O. One of theengaging projections 17c, namely 17c' (a linear guide key), is fixed toa contact terminal, i.e., a brush 9, which is in slidable contact withthe code plate 13a, fixed to the bottom of the linear guide groove 12b',to generate signals corresponding to focal length information duringzooming. The engaging projection 17c' is positioned approximatelydiagonal to the photographing plane.

The contacting terminal 9 is provided with a pair of brushes (electricarmatures) 9a, which are approximately perpendicular to a fixing part 9band in slidable contact with the code plate 13a, and a pair ofpositioning holes 9d (see FIG. 103). The pair of brushes 9a areelectrically continuous with each other via the fixing part 9b.

As illustrated in FIG. 30, on the code plate 13a, four types ofelectrode patterns ZC0, ZC1, ZC2 and ZC3 are provided Aligned in adirection perpendicular to the longitudinal direction of the code plate13a. The electrode patterns ZC0, ZC1, ZC2 and ZC3 form a predeterminedpattern in combination, so that a predetermined signal (i.e., voltage)may be output, when the pair of brushes 9a slide along the longitudinaldirection of the code plate 13a, conducting through the electrodepatterns ZC0, ZC1, ZC2 and ZC3 designated in advance corresponding tothe slide position.

On the inner periphery of the linear guide barrel 17 a plurality oflinear guide grooves 17a are formed parallel to the optical axis O. Aplurality of lead grooves 17b are formed on the linear guide barrel 17to extend through, and pass through, the peripheral wall of the linearguide barrel 17. The lead grooves 17b are formed oblique (inclined) tothe optical axis.

The second moving barrel 19 engages with the inner periphery of thelinear guide barrel 17. On the inner periphery of the second movingbarrel 19, a plurality of lead grooves 19c are provided in a directioninclined oppositely to the lead grooves 17b. On the outer periphery ofthe rear end of the second moving barrel 19 a plurality of followerprojections 19a, having a trapezoidal cross-sectional shape projectingaway from the optical axis in a radial direction, are provided. Followerpins 18 are positioned in the follower projections 19a. Each followerpin 18 consists of a ring member 18a, and a center fixing screw 18bwhich supports the ring member 18a in the follower projection 19a. Thefollower projections 19a are in slidable engagement with the leadgrooves 17b of the linear guide barrel 17, and the follower pins 18 arein slidable engagement with the linear guide grooves 16c of the thirdmoving barrel 16. With such an arrangement, when the third moving barrel16 rotates, the second moving barrel 19 moves linearly in the opticalaxis direction, while rotating.

On the inner periphery of the second moving barrel 19, the first movingbarrel 20 is engaged. In the first moving barrel 20, a plurality offollower pins 24, provided on an outer periphery of the rear thereof,are engaged with the corresponding inner lead grooves 19c, and at thesame time the first moving barrel 20 is guided linearly by a linearguide member 22. As shown in FIGS. 8 and 9, the linear guide member 22is provided with an annular member 22a, a pair of guide legs 22b, whichproject from the annular member 22a in the optical axis direction, and aplurality of engaging projections 28 which project from the annularmember 22a away from the optical axis in a radial direction. Theengaging projections 28 slidably engage with the linear guide grooves17a. The guide legs 22b are inserted between the inner peripheral faceof the first moving barrel 20 and the AF/AE shutter unit 21.

The annular member 22a of the linear guide member 22 is connected to therear of the second moving barrel 19, such that the linear guide member22 and the second moving barrel 29 are capable of moving along theoptical axis direction as a whole. In addition, the linear guide member22 and the second moving barrel 19 are capable of relative rotationaround the optical axis. On the outer periphery of the rear of thelinear guide member 22 a rear end flange 22d is provided having aplurality of engaging projections 28b which project away from theoptical axis in the radial direction. In front of the rear end flange22d there is provided an anti-dropping flange 22c, having a radiussmaller than the rear end flange 22d. Along the circumferentialdirection of the anti-dropping flange 22c, a plurality of notches 22eare formed, as shown in FIG. 8. On the inner periphery of the rear ofthe second moving barrel 19, a plurality of engaging projections 19b,projecting towards the optical axis in a radial direction, are providedas shown in FIG. 18. By inserting the engaging projections 19b into thenotches 22e, the engaging projections 19b are positioned between theflanges 22c and 22d, and by relative rotation of the linear guide member22, the engaging projections 19b are engaged with the linear guidemember 22 .With the above structure, when the second moving barrel 19rotates clockwise or counterclockwise, the first moving barrel 20 moveslinearly, forwardly and rearwardly in the optical axis direction, but isrestricted from rotating.

At the front of the first moving barrel 20, a barrier apparatus 35having barrier blades 48a and 48b is mounted, and on an inner peripheralface of the first moving barrel 20 the AF/AE shutter unit 21 having theshutter 27, consisting of three shutter blades 27a, is engaged and fixed(FIG. 12). The AF/AE shutter unit 21 is provided with a plurality offixing hollows 40a formed at even angular intervals on the outerperiphery of the shutter mounting stage 40 as shown in FIG. 10. Theplurality of follower pins 24 serve to fix the AF/AE shutter unit 21.The follower pins 24 are inserted and fixed in hollows 20a, formed onthe first moving barrel 20, and in the fixing hollows 40a. With thisarrangement the shutter unit 21 is secured to the first moving barrel 20as shown in FIG. 11. For example, the follower pins 24 may be fixed byan adhesive or by screws for example. For reference, numeral 41 (FIG.19) is a decorative plate secured to the front of the first movingbarrel 20.

As illustrated in FIGS. 12 and 19, the AF/AE shutter unit 21 is providedwith the shutter mounting stage 40, a shutter blade supporting ring 46fixed on the rear of the shutter mounting stage 40, and the lenssupporting barrel 50 (i.e., for the rear lens group L2) supported in astate of being capable of movement relative to the shutter mountingstage 40. On the shutter mounting stage 40, the front lens group L1, theAE motor 29, and the rear lens group driving motor 30, are supported.The shutter mounting stage 40 is provided, with an annular member 40fhaving a photographing aperture 40d. The shutter mounting stage 40 isalso provided with three legs 40b which project rearwards from theannular member 40f. Three slits are defined between the three legs 40b,and two of the slits comprise linear guides 40c, which slidably engagewith the respective pair of guide legs 22b of the linear guide member22, so as to guide the movement of the linear guide member 22.

The shutter mounting stage 40 supports an AE gear train 45, whichtransmits rotation of the AE motor 29 to the shutter 27, a lens drivinggear train 42, which transmits rotation of the rear lens group drivingmotor 30 to a screw shaft 43, photointerrupters 56 and 57, connected tothe flexible printed circuit board 6, and rotating plates 58 and 59,having a plurality of radially formed slits provided in thecircumferential direction. An encoder for detecting a rotation of therear lens group driving motor 30 consists of the photointerrupter 57 andthe rotating plate 59, and an encoder for detecting a rotation of the AEmotor 29 consists of the photointerrupter 56 and the rotating plate 58.

The shutter 27, a supporting member 47 which pivotally supports thethree shutter blades 27a of the shutter 27, and a circular drivingmember 49, which provides rotative power to the shutter blades 27a, arepositioned between the shutter mounting stage 40 and a shutter bladesupporting ring 46, secured to the shutter mounting stage 40. Thecircular driving member 49 is provided with three operating projections49a spaced at even angular intervals, which respectively engage witheach of the three shutter blades 27a. As shown in FIG. 12, the shutterblade supporting ring 46 is provided, at a front end thereof, with aphotographing aperture 46a and with three supporting hollows 46bpositioned at even angular intervals around the photographing aperture46a. On an outer periphery of the shutter blade supporting ring 46 thereis provided a deflection restricting member 46c, which is exposed fromthe linear guides 40c and which slidable supports the inner peripheralfaces of the pair of guide legs 22b.

The supporting member 47 positioned in front of the shutter bladesupporting ring 46 is provided with a photographing aperture 47a,aligned with the photographing aperture 46a, and with three shafts 47b(only one of which is illustrated in FIG. 12) at respective positionsopposite the three supporting hollows 46b. Each of the three shutterblades 27a are respectively provided with a shaft hole 27b into whichone end of each respective shaft 47b is inserted, with a blocking part(not shown) which prevents unwanted light from entering thephotographing apertures 46a and 47a at the other end, and with a slot27c, through which the operating projection 49a is inserted, between theone end and the other end thereof. The supporting member 47 is fixed tothe shutter blade supporting ring 46 in such a manner that each shaft47b, which supports a corresponding shutter blade 27a, is engaged with acorresponding supporting hollow 46b of the shutter blade supporting ring46.

On the outer periphery of the circular driving member 49, gears 49b areprovided to receive the rotation from the gear train 45. The supportingmember 47 is provided, at the position close to the three shafts 47b,with three arc grooves 47c, which are arched in the circumferentialdirection. The three operating projections 49a of the circular drivingring 49 engage with the slots 27c of the respective shutter blades 27athrough the three arc grooves 47c. The shutter blade supporting ring 46is inserted from the rear of the shutter mounting stage 40, to supportthe circular driving ring 49, the supporting member 47 and the shutter27, and is fixed on the shutter mounting stage 40 by screws.

At the rear of the shutter blade supporting ring 46, the lens supportingbarrel 50 is positioned such that the lens supporting barrel 50 iscapable of relative movement with respect to the shutter mounting stage40 via slide shafts 50 and 51. The shutter mounting stage 40 and thelens supporting barrel 50 are urged by a coil spring 3 fitted to theslide shaft 51, to move in opposite directions away from each other.Therefore, play between the supporting barrel 50 and the slide shaft 51is reduced. In addition, a driving gear 42a provided in the gear train42 is restricted to move in the axial direction, and on the innerperiphery thereof, an internal thread (not shown) is formed. The screwshaft 43, one end of which is fixed to the lens supporting barrel 50,engages the internal thread, and a feed screw structure is providedconsisting of the driving gear 42a and the screw shaft 43. In such amanner, when the driving gear 42a rotates clockwise or counterclockwisedue to driving by the rear lens group driving motor 30, the screw shaft43 respectively moves forwardly or rearwardly with respect to thedriving gear 42a and the lens supporting barrel 50. In other words, therear lens group L2 supported by the lens supporting barrel 50, movesrelative to the front lens group L1.

At the front of the shutter mounting stage 40, pressers 53 and 55, whichpress against respective motors 29 and 30, are screwed to the shuttermounting stage 40. The motors 29, 30 and the photointerrupters 56, 57are connected to the flexible printed circuit board 6. One end of theflexible printed circuit board 6 is fixed to the shutter mounting stage40. When the first, second and third moving barrels 20, 19 and 16, andthe AF/AE shutter unit 21 and the like are assembled, the aperture plate23 is fixed to the rear of the linear guide barrel 17. At the front ofthe fixed lens barrel block 12, an anti-dropping member 33, having acircular shape, is engaged.

At the front of the first moving barrel 20, which is positioned at thefront most part of the zoom lens barrel 10, the barrier apparatus 35,having pairs of barrier blades 48a and 48b, serving respectively asfollower barrier blades and main barrier blades, are provided. Towardsthe rear of the decorative plate 41, an annular plate 96 is fixed, andbetween the decorative plate 41 and the annular plate 96, the barrierblades 48a and 48b are connectively engaged. In addition, at the frontof the first moving barrel 20, between a front surface 20b and theannular plate 96, a barrier driving ring 96, having a pair of barrierdriving levers 98a and 98b, is rotatively provided. The barrier drivingring 97, is rotated clockwise or counterclockwise, by a barrierinterlocking gear 92 which drives rotatively upon receiving a rotationof the rear lens group driving motor 30, and via the barrier drivinglevers 98a and 98b opens or closes the main barrier blades 48b togetherwith the follower barrier blades 48a.

While in the above description of the present invention, the zoom lensconsisted of two groups, namely the front lens group L1 and the rearlens group L2, it should be understood that the present invention is notlimited to the embodiment disclosed above. In addition, in the aboveembodiment, the front lens group L1, and the rear lens group L2,supported by the lens supporting barrel 50, are provided as componentsof the AF/AE shutter unit 21, and the rear lens group driving motor 30is mounted to the shutter unit 21. With such a structure, although thesupporting structure and the driving structure of the rear lens group L2are simplified, the present zoom lens may also be realized in such amanner by making the rear lens group L2 a member apart from the AF/AEshutter unit 21. In this alternative, the AF/AE shutter unit 21 isprovided with the shutter mounting stage 40, the circular driving member49, the supporting member 47, the shutter blades 27, the shutter bladesupporting ring 46 and the like, and that the rear lens group L2 issupported by a supporting member other than the AF/AE shutter unit 21.

In the zoom lens camera of the present invention, the operation byrotation of the whole unit driving motor 25 and the rear lens groupdriving motor 30 will now be described.

As shown in FIG. 16, when the zoom lens barrel 10 is at the mostretracted (withdrawn) position, i.e., the lens-housed condition, whenthe power switch is turned ON, the whole unit driving motor 25 rotatesby a small amount in the clockwise direction. This rotation istransmitted, via a gear train 26 which is supported by a supportingmember 32, to the driving pinion 15. The third moving barrel 16 isrotated in the optical axis direction (i.e., is extended), the secondmoving barrel 19 and the first moving barrel 20 are extended by a smallamount in the optical axis direction, along with the third moving barrel16, which places the camera in a state capable of photographing, withthe zoom lens positioned at the widest position, i e., the wide end. Atthis time, due to the fact that the amount of movement of the linearguide barrel 17, with respect to the fixed lens barrel block 12, isdetected through the relative sliding movement between the code plate13a and the contacting terminal 9, the focal length of the zoom lens,i.e., the front and rear lens group L1 and L2, is also detected.

In the photographable state as above described, when the zoom "tele"switch is turned ON, the whole unit driving motor 25 drives clockwise,and rotates the third moving barrel 16 in the direction in which it isextended via the driving pinion 15 and the outer peripheral gear 16b.Therefore, the third moving barrel 16 is extended from the fixed lensbarrel block 12, according to the relationship between the femalehelicoid 12a and the male helicoid 16a, and at the same time, the linearguide barrel 17, which moves without relative rotation to the fixed lensbarrel block 12, because of the engaging projections 17c and the linearguide grooves 12b, moves forwardly in the optical axis directiontogether with the third moving barrel 16. At this time, the simultaneousengagement of the follower pins 18 with the lead groove 17b and thelinear guide groove 16c causes the second moving barrel 19 to moveforward relative to the third moving barrel 16 in the optical axisdirection, while rotating relative to and in the same direction as thethird moving barrel 16. The first moving barrel 20, which is guidedlinearly by the linear guide member 22 and the follower pins 24 whichare guided by the lead grooves 19c, moves forwardly in the optical axisdirection together with the AF/AE shutter unit 21, from the secondmoving barrel 19, without relative rotation to the fixed lens barrelblock 12. During such movements, because the position of the linearguide barrel 17 as it moves with respect to the fixed lens barrel block12 is detected through the relative sliding between the code plate 13aand the contacting terminal 9, the focal length can be set by the zoomoperation device 62.

When the zoom "wide" switch is turned ON, the whole unit driving motor25 drives counterclockwise, and the third moving barrel 16 is rotated inthe direction in which it is retracted such that the third moving barrel16 is retracted into the fixed lens barrel block 12 together with thelinear guide barrel 17. At the same time, the second moving barrel 19 isretracted into the third moving barrel 16, while rotating in the samedirection as that of the third moving barrel 16, and the first movingbarrel 20 is retracted into the rotating second moving barrel 19together with the AP/AE shutter unit 21. During the above retractiondriving, as in the case of extending driving as above described, therear lens group driving motor 30 is not driven.

While the zoom lens 10 is driven during the zooming operation, since therear lens group driving motor 30 is not driven, the front lens group L1and the rear lens group L2 move as a whole, maintaining a constantdistance between each other, as shown in FIG. 15. The focal lengthinputted via the zoom code plate 13a is indicated on the LCD panel 224.

At any focal length set by the zoom operating device 62, when therelease button 217B is depressed by a half-step, the CPU 210 obtainsfocusing information from the object distance measuring apparatus 64 andphotometering information from the photometering apparatus 65. In such astate, when the release button 217B is fully depressed, the CPU 210moves the whole unit driving motor 25 and the rear lens group drivingmotor 30 by an amount corresponding to the focal length information setin advance by the operation, and by the subject distance informationfrom the object distance measuring apparatus 64. This has the effect ofmoving the whole unit driving motor 25 and the rear lens group drivingmotor 30 to the specified focal length, bringing the subject into focus.Further, via the AE motor controlling circuit 66, the AE motor 29 drivesthe circular driving member 49 according to subject luminanceinformation obtained from the photometering apparatus 65, and drives theshutter 27 in order to satisfy the required exposure. After the shutterrelease operation, the whole unit driving motor 25 and the rear lensgroup driving motor 30 are both driven immediately, and the front lensgroup L1 and the rear lens group L2 are moved to the position prior toshutter release.

When a power switch 212 is turned OFF and the electric power isdisconnected, the zoom lens 10 is retracted to the lens housed positionas shown in FIG. 18 by the whole unit driving motor 25. Before thewithdrawal movement, the whole unit driving motor 25 is driven, and therear lens group L2 moves to the home position.

In regard to the movement control of the front lens group L1 and therear lens group L2 which is performed when the release button 217B isfully depressed, the rear lens group driving motor 30 moves the rearlens group L2 rearwardly away from the front lens group L1, by an amountcorresponding to the subject distance information obtained from theobject distance measuring apparatus 64 and the focal length informationset by the zoom operating device 31. At the same time, the whole unitdriving motor 25 moves the front lens group L1 by an amountcorresponding to the subject distance information obtained from theobject distance measuring apparatus 64 and the focal length informationset by the zoom operating device 31. Due to the movement of the frontlens group L1 and the rear lens group L2, the focal length is set andsubject focusing is performed. After completion of the shutter release,the rear lens group driving motor 30 and the whole unit driving motor 25are driven immediately, so that both lens groups L1 and L2 are returnedto the position they were at prior to the shutter release.

When the zoom operating device 62 is operated to the "wide" position,the whole unit driving motor 25 drives counterclockwise, and the thirdmoving barrel 16 is rotated in the retraction direction, and isretracted into a cylinder 11 of the fixed lens barrel block 12, togetherwith the linear guide barrel 17. At the same time, the second movingbarrel 19 is retracted into the third moving barrel 16, with a rotationsimilar to that of the third moving barrel 16, and the first movingbarrel 20 is retracted into the rotating second moving barrel 19together with the AF/AE shutter unit 21. During the above retractiondriving, and as in the case of extension driving as above mentioned, therear lens group driving motor 30 is not driven. When the power switch isOFF, the zoom lens 10 is retracted to the housed position as shown inFIG. 18, by driving the whole unit driving motor 25 accordingly.

A detailed description in regard to lens drive control, which is one ofthe characteristics of the zoom lens barrel of the zoom lens camera ofthe present embodiment of the present invention, will now be describedwith reference to FIGS. 24 and 25.

FIG. 24 illustrates the loci of the movements of the front lens group L1and the rear lens group L2, and FIG. 25 illustrates the range ofmovement of the rear lens group L2 compared to the front lens group L1.

In FIG. 24, line A represents the locus of movement of the front lensgroup L1, line B represents the locus of movement of the rear lens groupL2 before the release button is fully depressed, and line C representsthe locus of movement of the rear lens group L2 when the release buttonis fully depressed. As can be understood from FIG. 24, during focusing,the distance between the front lens group L1 and the rear lens group L2is wider at the "wide" end (i.e., "W" end) position, and is shorter atthe "tele" end (i.e., "T" end) position.

As shown in FIG. 25, before and during an operation of the zoomoperating device 62, the rear lens group L2 is positioned at the standbyposition, and the constant distance to the front lens group L1 ismaintained. When the release button is fully depressed, the rear lensgroup L2 moves rearwardly, namely to the right in FIG. 25, and moves tothe photographing position and focusing is performed. When the rear lensgroup L2 moves rearwardly, the initial position (i.e., the referenceposition) of the rear lens group L2 (i.e., the rear lens supportingbarrel 50) is detected via a photo sensor (not shown), and from theinitial moment of position detecting, a pulse counting operation iscommenced. When the pulse counting reaches a value corresponding to anamount of movement corresponding to the subject distance informationobtained from the object distance measuring apparatus 64 and the focallength information set by the zoom operating device 62, the rear lensgroup driving motor 30 is stopped.

In FIG. 25, the range indicated as "Adjusting Range", represents a rangecorresponding to the minimum value of the pulse counting from theinitial position, when the zoom lens barrel 10 is positioned at the"tele" end and the focused subject is at infinity. Therefore, the rearlens group L2 is moved rearwardly with respect to the front lens groupL1, by an amount, such as the adjusting quantity, from the initialposition.

FIG. 21 illustrates the state when the zoom lens barrel 10 is in the"wide" end position, before the release button has been fully depressed.FIG. 22 illustrates the state when the zoom lens barrel 10 is in the"wide" end position, immediately after the release button has been fullydepressed. As above described, from the state as shown in FIG. 22, afterthe shutter release is complete, the rear lens group driving motor 30 isdriven immediately, and the rear lens group L2 moves towards the frontlens group L1, returning the zoom lens barrel 10 to the state as shownin FIG. 21.

If the rear lens group driving motor 30 is not immediately driven aftercompletion of the shutter release from the state as shown in FIG. 22,the rear lens group L2 remains in the photographing position, if aserious external force or impact is made towards the front of the firstmoving barrel 20, in a direction towards the main body of the camera(i.e., namely to the right in FIG. 22), all the moving barrels, namely,the first moving barrel 20, the second moving barrel 19 and the thirdmoving barrel 16, will be forced into the main body of the camera, andin such a case, the rear lens group L2 may collide with a film F.Therefore, not only may the film F or the rear lens group L2 be damaged,but other devices within the camera may be damaged. Such a state isillustrated in FIG. 23.

However, because the lens drive control of the zoom lens barrel providedin the camera of the present embodiment immediately drives the rear lensgroup driving motor 30 after completion of the shutter release from thestate as shown in FIG. 22, the rear lens group L2 is moved towards thefront lens group L1 and is returned to the position as shown in FIG. 21.Thus, the above problem illustrated in FIG. 23 is unlikely to occur.

The above embodiment of the present invention refers to a three-stagedelivery zoom lens barrel; however, it should be understood that thepresent invention is not limited to such a lens barrel, and can beequally applied to a one-stage, two-stage or more than three-stagedelivery zoom lens barrel.

As described above, in accordance with the lens driving method of thezoom lens and the zoom lens barrel in the present invention, during thezoom operation, the front lens group and the rear lens group move as awhole without varying the distance between the two lens groups, andduring the release operation, the rear lens group moves rearwardly withrespect to the front lens group, and after completion of release, therear lens group moves towards the front lens group, so that both lensgroups are returned to the initial position that they were at during thezoom operation. Therefore, in a state that the lens barrel is extendedfrom the main body of the camera, if a serious external force or impactis made to the front of the lens barrel in a direction towards the mainbody of the camera, and the lens barrel is forced to be retractedaccordingly, it is unlikely that the rear lens group might collide withthe film, and therefore the film, the rear lens group or the lensdriving apparatus will not be damaged.

FIGS. 26 through 28 illustrate a front elevational view, a rearelevational view and a plan view of the lens shutter type camera of thepresent invention, respectively, provided with the zoom lens barrelshown in FIGS. 1 through 25.

At approximately a center of the front of a camera body 201, the zoomlens barrel 12 is mounted. On the front surface of the camera body 201,a light receiving element 65a for photometering, an AF sensor window64a, a finder window 207a of a finder optical system, a stroboscopiclamp 209, and a self-timer indicating lamp 229, are all provided. At thebottom of the camera body 201, a battery cover 202 is provided.

On the rear surface of the camera body 201, a rear cover 203, openingand closing for the purpose of loading or removing a film cartridge, arear cover opening lever 204, used to unlock the locking device to openthe rear cover 203, a green lamp 228, which indicates the result offocusing, a red lamp 227, which indicates the state of strobe charging,an eyepiece 207b, and a power (ON/OFF) button 212B, are provided.

On the top surface of the camera body 201, as viewed from the left ofthe drawing, a rewind button 216B, the LCD panel 224, a mode button214B, a driving button 215B, the release button 217B, the "wide" button62WB, and the "tele" button 62TB, are provided.

FIG. 29 illustrates a structure of the main internal components of thezoom lens camera of the present invention. The camera is provided withthe CPU 210, that controls the overall functions of the camera.

The CPU 210 drives and controls the whole unit driving motor 25, via thewhole unit driving motor controlling circuit 60, the rear lens groupdriving motor 30, via the rear lens group driving motor controllingcircuit 61, and the AE motor 29, via the AE motor controlling circuit66. The CPU 210 also controls, via a film feeding control circuit 225, afilm transport motor 226 which performs loading, winding and rewindingof film. The CPU 210 further controls flashing of a strobe (i.e, anelectronic flash) via a strobe device 231.

The CPU 210 is capable of operation when a battery 211 is loaded, andexecutes functions according to the I/O state (i.e., ON/OFF) of eachswitch input thereto, namely the state of the power switch 212, a rearcover switch 213, a mode switch 214, a driving switch 215, a "tele"switch 62T, a "wide" switch 62W, a rewind switch 216, the photometeringswitch SWS, and the release switch SWR.

The power switch 212 is connected to the power button 212B, and when thepower switch 212 is turned "ON" when the electric power is "OFF" (i.e.,the electric power of the battery 211 is cut), the power switch 212turns the electric power "ON" (i.e., the electric power of the battery211 is supplied), and when the power switch 212 is turned "OFF" when theelectric power is "ON", the power switch 212 turns the electric power"OFF".

The rear cover switch 213 is associated with the opening or closing ofthe rear cover 203 by a connection to the rear cover 203. According tochanges in the state of the rear cover 203, the rear cover switch 213executes a film loading operation by driving the film transport motor226, or resets a film counter.

The mode switch 214 is used to change photographing modes, and isconnected to the mode button 214B. As the mode switch 214 changes to an"ON" state, photographing modes are changed, such as an auto strobeflashing mode, a forced strobe flashing mode, a strobe flashingforbidding mode, a long exposure mode, or a bulb mode etc.

The driving switch 215 changes between various driving modes, and isconnected to the driving button 215B. As the driving switch 215 changesto an "ON" state, driving modes are changed, such as a framephotographing mode, a self-timer mode, a continuous photographing mode,or a multiple exposure mode etc.

The "tele" switch 62T is connected to the "tele" button 62TB. When the"tele" switch 62T is "ON", the whole unit driving motor 25 is driventoward the "tele" end.

The "wide" switch 62W is connected to the "wide" button 62WB. When the"wide" switch 62W is "ON", the whole unit driving motor 25 is driventoward the "wide" end.

The photometering switch SWS and the release switch SWR are connected tothe release button 217B. When the release button 217B is half depressed,the photometering switch SWS is turned "ON", and when the release button217B is fully depressed, the release switch SWR is turned "ON". Duringthe time that the release button 217B is between the half-depressed andfully-depressed conditions, the photometering switch SWS is maintainedin the "ON" state. When the photometering switch SWS is "ON",photometering and object distance measuring operations are executed.When the release switch SWR is turned "ON", the whole unit driving motor25 and the rear lens group driving motor 30 are driven so that the frontlens group L1 and the rear lens group L2 may be moved to a position atwhich the subject is brought into focus according to the result of theobject distance measurement. The AE motor 29 is also driven and exposureprocessing is executed according to the determined photometering value.After exposure is complete, the whole unit driving motor 25 and the rearlens group driving motor 30 are driven, and the front lens group L1 andthe rear lens group L2 are returned to their respective initialpositions. In addition, the film transport motor 226 is driven and thefilm is wound by one frame.

An output from a DX-code information input circuit 218 is input to theCPU 210, which provides information regarding the ISO speed of film.Also input to the CPU 210 is zoom code information input from a zoomcode circuit 219, which provides information regarding the present lensposition from the code plate 13a, a zoom pulse input circuit 220, an AEpulse input circuit 221, an AF reference pulse input circuit 222, and awind pulse input circuit 223, which provides information regardingdriving of the film and the amount of driving thereof. Additionally, anAF home position detecting circuit 232, is input to the CPU 210.

A number of indicators, for example, the LCD panel 224, which indicatesa current focal length, a number of frames photographed, an exposuremode or the like, the red lamp 227, which indicates the state of strobecharging, the green lamp 228, which indicates the result of focusingfrom the object distance measuring apparatus 64, and the self-timerindicating lamp 229, which indicates the operation of the self-timer,are connected to the CPU 210.

In an EEPROM 230, data inherent to the camera at the time of assembling,such as data regarding an AE adjustment thereof, or data set by aphotographer, such as the exposure mode or the number of framesphotographed, are stored.

As shown in FIG. 31, the zoom code information input circuit (electricalcircuit) 219 is provided with four resistors (R0, R1, R2, R3) connectedin series. The resistor R0 is grounded while a reference voltage V_(DD)is applied to the resistor R3. Between the resistor R0 and ground theelectrode pattern ZC0 is connected, and between resistors R0 and R1 theelectrode pattern ZC1 is connected, between resistors R1 and R2 theelectrode pattern ZC2 is connected, and between resistors R2 and R3 theelectrode pattern ZC3 is connected. In addition, an A/D conversion inputport of the CPU 210 is connected between the resistors R2 and R3.

As shown in FIG. 30 (A), the code plate 13a is provided with fourindependent electrode patterns (zoom codes) ZC0, ZC1, ZC2 and ZC3 formedon an insulating substrate 13b. The electrode patterns, namelyconducting plates, ZC0, ZC1, ZC2 and ZC3 are connected respectivelybetween the resistors R0, R1, R2 and R3. The contacting terminal 9 isprovided with a pair of brushes 9a conducting with each other via aconductive part 9b. The brushes 9a are formed to move in slidablecontact along the code plate 13a, so that any two patterns among theelectrode patterns ZC0, ZC1, ZC2 and ZC3 may conduct with each other.Therefore, if any two patterns among the electrode patterns ZC0, ZC1,ZC2 and ZC3 conduct with each other, according to the combination ofconduction, the output voltage of the zoom code information inputcircuit 219 will vary, as shown in FIG. 30 (C) and FIG. 30 (E). The CPU210 performs an A/D conversion, whereby the output voltage is convertedinto a digital value. The CPU 210 further converts the converted digitalvalue into a corresponding zoom code. The CPU 210 then detects theposition of the zoom lens according to the zoom code.

In the present embodiment of the present invention, as shown in FIG. 30(D), the voltages corresponding to the contacting positions of thebrushes 9a are converted into seven zoom codes, namely 0, 1, 2, 3, 4, 5and 6. Each of the seven codes represents a position of the lens, i.e.,the zoom code 1 represents the housed position, the zoom code 2 the"wide" position, the zoom code 6 the "tele" position, the zoom codes 3through 5 represent the intermediate positions between the "wide"position and the "tele" position, and the zoom code 0 represents theposition between the housed position and the "wide" position. At theintermediate positions, the zoom codes 3, 4 and 5 are repeated fourtimes in that order, and the zoom range is divided and coded intofourteen zoom step codes. In the present embodiment of the presentinvention, the zoom step 0 is assigned to the "wide" end position, andthe zoom step 13 at the "tele" end position, and the zoom steps 1through 12 are assigned to positions between the "wide" end and the"tele" end positions.

FIG. 31 shows the zoom code information input circuit 219 with exemplaryvalues for resistors R0, R1, R2 and R3. FIG. 32 is a table showing anexample of the relationship among the short-circuiting of resistors R1,R2, R3; the zoom code; the output V₀ of the zoom code information inputcircuit 219; and the threshold voltage.

The zoom pulse input circuit 220 is provided with an encoder consistingof the photointerrupter 1 and the rotating plate 2. The input of thephotointerrupter 1, varied according to the passage of the slit of therotating plate 2 which rotates in accompaniment to the rotation of thedriving shaft of the whole unit driving motor 25, is output as a zoompulse.

The AE pulse input circuit 221 is provided with an encoder consisting ofthe photointerrupter 57 and the rotating plate 59. The input of thephotointerrupter 57, which varies according to the passage of the slitof the rotating plate 59 which rotates in accompaniment to the rotationof the driving shaft of the AE motor 29, is output as an AE pulse. Therotating plate 59 is arranged such that is rotates by less than one fullturn (i.e., less that 360°).

The AF reference pulse input circuit 222 is provided with an encoderconsisting of the photointerrupter 56 and the rotating plate 59. Theinput of the photointerrupter 56, which varies according to passage ofthe slit of the rotating plate 59 which rotates in accompaniment to therotation of the driving shaft of the rear lens group driving motor 30,is output as an AF pulse.

The AF home position detecting circuit 233 detects whether the rear lensgroup L2 is positioned at the reference position, namely the positionclosest to the front lens group L1 (i.e., the AF home position). In thepresent embodiment of the present invention, the position of the rearlens group L2 is controlled by the AF pulse number, with respect to theAF home position. The AF home position detecting circuit 233 is providedwith a photointerrupter 301, and the position at which a chopper 302(i.e., a chopper plate 302a), which moves integrally with the rear lensgroup L2, blocks the light path of the photointerrupter 301, is set asthe AF home position, and according to the variation of output of thephotointerrupter 301, the rear lens group L2 is detected to be at the AFhome position (see, for example, FIG. 37).

FIG. 33 illustrates an electrical circuit of the strobe device 231.

A strobe circuit 500 is provided with a ground terminal GND, a voltageinput terminal VBAT and three strobe controlling terminals STRG, CHENand RLS. The battery voltage of the camera is supplied to the terminalsVBAT and GND. The controlling terminals STRG, CHEN and RLS arerespectively connected to the CPU 210. The terminal STRG is a strobeflashing signal (strobe trigger) input terminal, and in an normal statethe terminal STRG is set to the L level (i.e., logic low), and onoccasion of strobe flashing, a signal at the H level (i.e., logic high)is input. To the terminal CHEN the charging signal is input. At the Lstate, charging is not performed, while at the H state, charging isperformed. The terminal RLS is a charging voltage output terminal andoutputs the voltage corresponding to the charging voltage to the A/Dconverter of the CPU 210.

The battery charging and the monitoring of the charging voltage will nowbe described.

As above described, the charging is performed by setting the level ofthe terminal CHEN to the H level (i.e., the charging signal "ON"). Whenthe terminal CHEN is at the H level, the level of the base of atransistor 501 becomes H and transistor 501 turns ON. When thetransistor 501 is ON, a voltage transforming circuit (i.e., a DC-DCconverter), consisting of a transistor 502, a primary winding 511 and asecondary winding 512 of a transformer 510, and a diode 521, isactivated, and charging of a capacitor 530 is performed.

In addition, since the signal at the H level is supplied to the terminalCHEN, transistors 573 and 576 also turn ON, and a Zener diode 570becomes connected to each terminal of the capacitor 530 via a transistor576 and resistors 577 and 578.

In the present embodiment, the capacitor 530 is charged to 300 volts.The breakdown voltage of the Zener diode 570 is 230 volts. As thecapacitor 530 charges and the voltage applied to the Zener diode 530increases beyond the breakdown voltage of the Zener diode 530, currentflows through the Zener diode 570 (Zener current).

As the Zener current flows, a voltage corresponding to the chargedvoltage of the capacitor 530 is applied to the terminal RLS, as dividedby a voltage divider set up by resistors 577 and 578.

As above described, during charging when the terminal CHEN is at the Hlevel, the resistors 577 and 578 are connected in series to eachterminal of the capacitor 530. Until the charged voltage of thecapacitor 530 exceeds the breakdown voltage, current does not flow. Asthe charging of the capacitor 530 continues, and the voltage applied tothe Zener diode 570 increases beyond the breakdown voltage, a differencebetween the charged voltage of the capacitor 530 and the breakdownvoltage of the Zener diode 570 is divided by resistors 577 and 578. Thedivided voltage value, which corresponds to the voltage across theresistor 778, is applied to the terminal RLS.

As shown in FIG. 29, the voltage applied to the terminal RLS is input tothe CPU 210. Specifically, the voltage applied to the terminal RLS isapplied to the A/D converter built into the CPU 210.

The strobe flashing operation will now be described.

When the charging voltage of the capacitor 530 is more than or equal tothe voltage level necessary for flashing, strobe flashing is performedby inputting the strobe trigger to the terminal STRG.

When the strobe trigger is input to the terminal STRG, in other words,when the signal at the H level is input to the terminal STRG, an SCR(i.e., a thyristor) is turned ON such that the SCR is in a conductivestate. At that time, in accordance with the sudden discharge of acapacitor 544 connected to the primary winding of a transformer 550, thesecondary winding of the transformer 550 will have a high voltage. Thehigh voltage in the secondary winding of the transformer 550 is appliedto a trigger terminal 551 of a xenon tube 560, and flashing of the xenontube 560 is performed.

FIGS. 37 through 40 illustrate the structure to detect the AF homeposition, which is the initial position of the rear lens group L2. TheAF home position is a position where the rear lens group L2 is close tothe front lens group L1. By making this position the reference positionfor focusing, the rear lens group L2 moves along the optical axis awayfrom the front lens group L1. When the power is "ON", the shutterrelease has completed, the lens is housed, and at zoom step positionsother than the zoom steps 0 through 4, the rear lens group L2 iscontrolled to maintain the AF home position with respect to the frontlens group L1. At zoom steps 0 through 4, the rear lens group L2 ismoved to the rearward position from the AF home position by an amountcorresponding to the specified pulse value AP1.

The rear lens supporting barrel 50 is supported, via the pair of slideshafts 51 and 52, so as to be capable of moving towards the shuttermounting stage 40 along the optical axis. One end of the slide shafts 51and 52 are fixed on shaft supporting bosses 50b and 50c projecting fromthe outer periphery of the lens supporting barrel 50. The slide shaft 51is inserted to be slidably supported by a slide bearing 51a fixed to theshutter mounting stage 40.

One end of the screw shaft 43 is fixed to a shaft supporting boss 50aprojecting from the outer peripheral face of the lens supporting barrel50, close to the shaft supporting boss Sob. The screw shaft 43 isengaged with the driving gear 42a, which is supported by the shuttermounting stage 40 and the shutter 27, such as to be rotatable, but notmovable in the axial direction. When the driving gear 42a is driven bythe rear lens group driving motor 30, the screw shaft 43 moves forwardlyand rearwardly with respect to the driving gear 42a, and the lenssupporting barrel 50, namely the rear lens group L2 supported by thelens supporting barrel 50, is moved relative to the front lens group L1.In order to prevent backlash between the screw shaft 43 and the drivinggear 42a, the rear lens group urging coil spring 3 is tilted to theslide shaft 51 and is engaged with the slide bearing 51a and the shaftsupporting boss 50b. The rear lens group urging coil spring 3 forces thelens supporting barrel 50 in the direction away from the shuttermounting stage 40, in other words, towards the rear of the shuttermounting stage 40. Thus backlash is prevented.

At the front of the shutter mounting stage 40, namely the presser 55,the photointerrupter 301 and the chopper 302 which comprise the AF homeposition detecting circuit 232, are mounted. The photointerrupter 301 ismounted to the flexible printed circuit board 6, and is fixed on theshutter mounting stage 40. The chopper 302 is slidably supported by achopper guide shaft 303 and has its front end supported by the presser55. The chopper 302 is urged towards the shutter mounting stage 40, inother words, rearwards in the optical axis direction, by a chopperurging spring 304 mounted between the chopper 302 and the presser 55.The chopper 302 is provided with the chopper plate 302a, which isinserted in the slit of the photointerrupter 301, and when the chopper302 is at the rearward position owing to the force of the chopper urgingspring 304, the optical path of the photointerrupter 301 is open. Whenthe chopper 302 moves to the specified position against the force of thechopper urging spring 304, the optical path of the photointerrupter 301is blocked.

At the ends of the screw shaft 43 and at one end of the slide shaft 51,a stopper plate 306 is fixed via a lock washer 305. A chopper presser306a is integrally provided on the stopper plate 306, which contacts thechopper 302 and moves the chopper 302 forwardly against the force of thechopper presser urging 304 when the lens supporting barrel 50 movesforwardly. The chopper presser 306a is also contacted with a projection302b of the chopper 302 when the lens supporting barrel 50 (i.e., therear lens group L2) reaches a predetermined position closer to theshutter mounting stage 40. Due to the further forward movement of thelens supporting barrel 50, the chopper presser 306a moves the chopper302 against the force of the chopper urging spring 304. When the lenssupporting barrel 50 moves to the AF home position close to the shuttermounting stage 40, the chopper plate 302a of the chopper 302 blocks theoptical path of the photointerrupter 301. By checking the output of thephotointerrupter 301, the CPU 210 detects whether the rear lens groupL2, namely the lens supporting barrel 50, is at the AF home position ornot.

The function of the present zoom lens camera, the following discussionwill be made with reference to flow charts shown in FIGS. 41 through 73.The processes are executed by the CPU 210 based on the program stored inthe internal ROM of the CPU 210.

[The Main Process]

FIG. 41 is a flow chart showing the main process of the camera in thepresent invention. When the battery is loaded into the camera, the CPU210 commences the main process, and then enters a standby state andwaits for an operation to be performed by the photographer.

In the main process, the reset process (FIG. 42), indicated at stepS0001, is executed. In the reset process, hardware initialization, suchas each port of the CPU 210, RAM initialization, test function process,reading of adjustment data, shutter initialization, AP lensinitialization, and lens housing processing, are executed.

After completion of the reset process, at step S0003 through step S0053,checks are executed to check whether an error flag is set, the rewindswitch 216 is ON, the state of the rear cover switch 213 changes, thepower is ON, the state of the power switch 212 changes from ON to OFF,the "tele" switch 62T is ON, the "wide" switch 62W is ON, the drivingswitch 215 is changed from OFF to ON, the mode switch 214 is changedfrom OFF to ON, the photometering switch SWS is changed from OFF to ON,and whether the charging demand flag is set. The processes associatedwith each of the checks are executed according to the result of thechecks.

At step S0003, if the error flag is set (i.e., error flag is set to 1),it indicates that an error has occurred during at least one of the aboveprocesses in the reset process. To clear the error flag, errorinitialization processes from steps S0005 through S0013 are repeateduntil the error flag has cleared. At step S0005 the CPU 210 waits for achange in state of any of the switches, and after a change, at stepsS0006 through S0009, the error flag is reset, a shutter initializationprocess (FIG. 51) and an AF lens initialization process (FIG. 43) areexecuted. Then at step S0011 it is checked as to whether the error flaghas been set during the above processes (S0006-S0009), and if the errorflag is set, control returns to step S0003 and the processes from stepS0005 are repeated. If the error flag is not set at step S0011, theerror state has been resolved, and control returns to step S0003 after alens housing process (FIG. 44) has been executed at step S0013.

When the error flag is cleared, and when the power is OFF, at stepS0015, step S0019, step S0023, step S0025 and step S0029, theabove-mentioned checks are repeated, namely it is checked whether therewind switch 216 is ON, the state of the rear cover switch 213 haschanged, the power is ON, and whether the power switch 212 is changedfrom ON to OFF. When the rewind switch 216 is turned ON, or when thestate of the rear cover switch 213 is changed, or when the power switch212 is changed from ON to OFF, the following processes are executed.

At step S0015, if the rewind switch 216 is ON, the rewind motor isdriven and the film rewind is executed at step S0017.

At step S0019, if the state of the rear cover switch 213 changes, namelythe rear cover is closed or opened, the rear cover processes, such asresetting of the film counter or the film loading process, are executedat step S0021.

At steps S0023 and S0025, if the power switch 212 is changed from OFF toON, the power is turned ON, and the lens extension process is executedat step S0027. Each time the power switch is turned ON, the CPU 210turns the power ON if the power is OFF, and turns the power OFF if thepower is ON.

When the power is ON, control proceeds from step S0023 to step S0029,and the processes from steps S0029 to S0053 are executed. In theprocesses from steps S0029 to S0053, checks are performed to determinewhether the power switch 212 is changed from ON to OFF, the "tele"switch 62T is ON, the "wide" switch 62W is ON, the driving switch 215 ischanged from OFF to ON, the mode switch 214 is varied from OFF to ON,the photometering switch SWS is varied from OFF to ON, and whether thecharging demand flag is set.

At step S0029, if the power switch 212 is varied from ON to OFF, thepower is turned OFF, and the lens housing process (FIG. 44) is executedat step S0031. In the lens housing process the lens barrel is withdrawnto the housed position.

At step S0033, if the "tele" switch 62T is turned ON, a zoom "tele"movement process (FIG. 47) is executed at step S0035. In the zoom "tele"movement process the whole unit driving motor 25 is driven in the lensextension direction.

At step S0037, if the "wide" switch 62W is turned ON, a zoom "wide"movement process (FIG. 48) is executed at step S0039. In the zoom "wide"movement process the whole unit driving motor 25 is driven in the lensretraction direction.

At step S0041, if the driving switch 215 is varied from OFF to ON, adrive setting process is executed at step S0043. Though not shown indetail, the drive setting process is a process to select the drivingmode from amongst the frame photographing mode, the continuousphotographing mode, the multiple exposure mode, the self-timer mode, orthe like.

At step S0045, if the mode switch 214 is varied from OFF to ON, a modesetting process is executed at step S0047. Though not shown in detail,the mode setting process is a process to select the exposure mode fromamongst the strobe autoflashing mode, the forced strobe flashing mode,the strobe flashing prevention mode, the red-eye reduction mode, thelong exposure mode, the bulb mode, or the like.

At step S0049, if the photometering switch SWS is varied from OFF to ON,a photographing process (FIG. 49) is executed at step S0051.

At step S0053, if the charging demand flag is set, a main chargingprocess (FIG. 50) is executed at step S0055, and the charging process ofthe strobe device 231 is executed.

When the power is ON, the above processes from steps S0003 through S0055are repeated according to the operation of the photographer, and when nooperation is being undertaken, the standby state is maintained, i.e., astate ready for photographing.

[The Reset Process]

FIG. 42 is a flow chart showing the reset process which is performed atstep S0001 of the main process. In the reset process the followingprocesses are executed, namely, hardware initialization of each port ofthe CPU 210, RAM initialization, calling of the test function, readingof adjusting data, initialization of the shutter, initialization of theAF lens, and the lens housing processing.

At step S1101, the initialization of hardware, i.e., initializing thelevels of each port of the CPU 210 is executed, and at S1103 theinitialization of RAM, i.e., to clear the RAM in the CPU 210 isexecuted.

At step S1105 the test function process (FIG. 68) is executed, namelyeach function of the camera is tested by an external measuringapparatus, such as a computer, during or after assembly. In the testfunction process of the present embodiment of the present invention,although commands regarding the function to be tested are output fromthe external measuring apparatus, the actual process is executed by theCPU 210.

At step S1107, adjusting data is read from the EEPROM 230. The adjustingdata includes exposure adjusting value data, focus adjusting value data,and diaphragm adjusting data. The exposure adjusting value data adjustsfor an error between a design diaphragm value and the actual diaphragmvalue, or adjusts for differences due to different lenses havingdifferent transmittances. The diaphragm adjusting data detects whetherthe difference between the designed degree of opening of the shutterblade and the actual degree of opening thereof, has been adjusted withrespect to the number of AE pulses detected by the AE encoder upondriving of the AE motor 29. If the adjustment has been performed, thediaphragm adjusted value is stored in the EEPROM 230, as part of theadjusting data.

At step S1109, the shutter initialization process is executed tocompletely close the shutter blades 27a. In the present embodiment ofthe present invention, since the opening of the shutter blades 27a isoperated by the AE motor 29, there is a possibility that the battery maybe removed while the shutter is open, and additionally a possibilityexists that the battery is loaded while the shutter is open. Therefore,the AE motor 29 is driven in a direction to close the shutter blades 27a(shutter closing direction), and sets the closed condition wherein theshutter blades 27a are in contact with an initial position stopper (notshown).

At step S1111, the AF lens initialization process (FIG. 43) is executed,namely, the rear lens group L2 is moved to the initial position at whichit is extended furthest. In the present embodiment, the rear lens groupdriving motor 30 is driven to move the rear lens group L2 forwardly tothe furthest extended position, i.e., close to the front lens group L1,as an initial position.

At step S1113, it is checked whether the error flag has been set, and ifthe error flag has been set, control returns without executing anyfurther process. If the error flag has not been set, control returnsafter executing a lens housing process (FIG. 44), at step S1115.

In the lens housing process, the barrier blades 48a and 48b are closedby moving the lens barrel rearwardly to the housed position within thecamera body 201, by driving the whole unit driving motor 25. Since theerror flag will be cleared during normal usage, the lens housing processwill be executed. If the error flag is set to 1, the housing(withdrawing) of the lens is stopped since it can not be guaranteed thatthe rear lens group L2 is at the initial position (i.e., the AF homeposition) during the AF initialization process. If the lens housingprocess is executed in such a state, a possibility exists that the rearlens group L2 may collide with the aperture plate 14, so the lenshousing process is canceled.

[The AF Lens Initialization Process]

FIG. 43 is flow chart showing the AF lens initialization process. In theAF lens initialization process, if the lenses are housed, the whole unitdriving motor 25 is driven clockwise, the rear lens group driving motor30 is connected Lo an unillustrated barrier driving gear device, and thefront lens group L1 and the rear lens group L2 are moved as a whole tothe "wide" position by the whole unit driving motor 25. The rear lensgroup L2 is moved to the AF home position, namely the position at whichit will be closest to the front lens group L1, by driving the rear lensgroup driving motor 30.

If the lenses are at any position other than the housed position, thewhole unit driving motor 25 is driven clockwise, and if one of the zoomcodes is detected, the rear lens group driving motor 30 is driven andthe rear lens group L2 is moved to the AF home position, namely theposition closest to the front lens group L1.

Since the rear lens group driving motor 30 is connected to the barrierdriving gear device at the housed position, and is connected to the rearlens driving gear device at positions other than the housed position,the whole unit driving motor 25 must be driven to move the front lensgroup L1 and the rear lens group L2 to a position other than the housedposition (i.e., to the "wide" position or further) when the rear lensgroup L2 is to be driven.

At step S1201, the whole unit driving motor 25 is driven clockwise,namely in the direction for extending the lenses. If the lenses arehoused, the barrier driving device is detached from the barrier drivinggear and engaged with the lens driving gear, so that the rear lens groupL2 is in a state capable of be driven.

At step S1203, the CPU 210 performs an A/D conversion of the voltageinput from the zoom code input circuit 219 and converts the obtaineddigital value into a zoom code. At step S1205, the CPU 210 checks theconverted zoom code, and if the code is in the range 2 through 6 at stepS1205, the whole unit driving motor 25 is stopped immediately at stepS1207. In the present embodiment, zoom code 1 indicates the housedposition, zoom code 2 indicates the "wide" end position, zoom code 6indicates the "tele" end position, zoom codes 3, 4 and 5 indicateintermediate zoom positions, and zoom code 0 indicates the "OFF" state.In the processes of steps S1201 through S1207 the lens barrels 16, 19and 20 are extended until a zoom code in the range 2 to 6 is detected.

At step S1209, when the whole unit driving motor 25 is stopped, an AFpulse confirmation process (FIG. 53) is executed and the rear lens groupL2 is moved to the AF home position. The AF pulse confirmation processis characterized in that the rear lens group driving motor 30 is drivento rotate in forward and reverse directions to remove so-called "biting"of the mechanical components, such as the cam follower pin into the camgroove. After the rear lens group L2 is moved to the AF home position,control is returned.

[The Lens Housing Process]

FIGS. 44 and 45 show a flow chart of the lens housing process. In thelens housing process the front lens group L1 and the rear lens group L2are returned to the housed position. That is, the process is one inwhich the rear lens group L2 is returned to the AF home position by therear lens group driving motor 30, and the lenses, i.e., the front lensgroup L1 and the rear lens group L2, are driven to the housed positionby the whole unit driving motor 25, and then the lens barrier is closed.

At step S1301, when the lens housing process is called, the whole unitdriving motor 25 is driven in the clockwise direction, namely in the"tele" zoom direction. At step S1303 the zoom code input process (FIG.52) is executed until the present zoom code, namely the zoom codecorresponding to the lens position at the time at which the lens housingprocess is called, is detected. If the zoom code is detected at stepS1305, then at step S1307 driving of the whole unit driving motor 25 isstopped. Subsequently, at step S1309, it is judged whether the rear lensgroup L2 is at the AF home position. If the rear lens group L2 is not atthe AF home position at step S1309, the AF return process (FIG. 54) isexecuted and the rear lens group L2 is moved to the AF home position.

If the lens housing process is performed when the rear lens group L2 isnot at the AF home position, namely the rear lens group L2 is projectingtowards the film, the rear lens group L2 may collide with the apertureplate 14 of the camera body before the lenses reach the housed position.For the purpose of avoiding such an occurrence, the rear lens group L2is returned to the AF home position before the lenses are housed, namelybefore the counterclockwise driving of the whole unit driving motor 25.

When the lens housing process is called, if the lenses are positioned atthe "wide" end position, there exists a possibility that the rear lensgroup driving motor 30 may not be connected to the movement device ofthe rear lens group L2 but instead connected to the barrier openingdevice. If the rear lens group driving motor 30 is connected to thebarrier opening device, and if at the same time the rear lens group L2is extended from the AF home position, the rear lens group L2 will notmove to the AF home position even when the rear lens group driving motor30 is driven.

In the processes of steps S1301 through S1307, the lenses are drivenonce beyond the "wide" end position, to the "tele" side, as shown inFIG. 34, so that the rear lens group driving motor 30 will be connectedto the driving device of the rear lens group L2 after S1307. By drivingthe rear lens group driving motor 30 in the AF return process at stepS1311, after it has been judged at step S1309 that the rear lens groupL2 is not positioned at the AF home position, the rear lens group L2 canbe surely be moved.

At step S1309, if the rear lens group L2 is judged to be positioned atthe AF home position, the CPU 210 skips the AF return process (stepS1311), and proceeds to the movement process for housing the lenses atstep S1312.

At step S1312, the movement of the lenses to the "wide" end is startedby driving the whole unit driving motor 25 counterclockwise, and at stepS1313 a two-second timer is started. Subsequently, at steps S1315through S1329, before the end of the two-second timer, the zoom code,which varies according to the movement of the lenses, is input to detectthe lenses reaching the "wide" end position.

At step S1315, the CPU judges whether the timer has expired. The phrase"time expires" refers to the case in which the variation of the zoomcode is not detected within two seconds and where the movement of thelenses is stopped. If the time has not expired, at step S1321, the zoomcode input process is called and the zoom code is input. Whether thezoom code has changed is judged at step S1323, and if the zoom code haschanged, the two-second timer is reset. If it is judged that the zoomcode has not changed at step S1323, it is then judged at step S1327whether the lenses have reached the housed position. If the Lenses havenot reached the housed position, it is judged whether the lenses havereached the "wide" end position at step S1329. If neither the housedcode nor the "wide" code is detected, the CPU 210 repeats the processesfrom step S1315.

If the time expires while repeating the above processes, at step S1317the CPU 210 stops the whole unit driving motor 25, and sets the errorflag to 1 to indicate the occurrence of an error (step S1319), and thelens housing process is ended. Control returns to the position at whichthe present process was called.

If at step S1329, the "wide" code was detected during the above process,then a four-second timer is set at step S1331, and the counter is resetto 0 (step S1335), and the processes from steps S1337 to S1361 arerepeated until the four-second timer expires. Here, a process isexecuted in which the rear lens group driving motor 30 is drivenintermittently while the whole unit driving motor 25 is drivencontinuously, namely the lenses are moved beyond the "wide" end positiontowards the housed position.

In the camera 1 of the present embodiment, as already described, themovement of the rear lens group L2 and the opening and closing of thebarrier are executed by the rear lens group driving motor 30. When thelenses are positioned on the "tele" side of the "wide" end position, therear lens group driving motor 30 is connected to the driving device ofthe rear lens group L2 and is not connected to the barrier openingdevice. However, when the lenses are positioned toward the housedposition from the "wide" end position, or when the lenses are beinghoused, the barrier/lens switching gear device must be switched so thatthe rear lens group driving motor 30 is connected to the barrier openingdevice.

Although the switching of the gears is designed to be executed through acam device according to the movement of the lenses, in order to ensurethat the barrier/lens switching gear device will surely be engaged withthe teeth of the barrier driving gear at this time, the rear lens groupdriving motor 30 is driven while the lenses are being moved from the"wide" end position to the housed position. To ensure the engagement ofthe barrier/lens switch gear, after step S1311 where thecounterclockwise driving of the whole unit driving motor 25 iscommenced, the rear lens group driving motor 30 is designed to be drivenintermittently.

At step S1337, it is judged whether the time of the four-second timerexpires. Normally, the time of the four-second timer will not be up aslong as an error has not occurred, and an N (NO) judgement is made atstep S1337. At step S1345, after waiting 1 ms, the counter isincremented at step S1347, and it is judged whether the value of thecounter has reached 100 at step S1349. If the value of the counter isless than 100, an N judgement is made at step S1349, and then at stepS1351, it is judged whether the value of the counter has reached 80 atstep S1351.

If the value of the counter is less than 80 at step S1351, the zoom codeinput process is called and the zoom code is input at step S1359. If thehoused code is not detected at step S1361, control returns to step S1337and the processes are repeated. At step S1351, when the value of thecounter reaches 80, the counterclockwise driving of the rear lens groupdriving motor 30 is executed at step S1353. If the value of the counterreaches 100, the counter is reset to 0, and the rear lens group drivingmotor 30 is stopped, at steps S1355 and S1357.

Since the waiting time of ims is set at step S1345, the above processesare repeated at a 100 ms cycle. Therefore, when the value of the counteris between 0 and less than 80, namely, until 80 ms passes after thedetection of the "wide" end code, only the whole unit driving motor 25is driven. When the value of the counter is 80 or more and less than100, namely, 80 ms or more and less than 100 ms have passed since thedetection of the "wide" end code, both the whole unit driving motor 25and the rear lens group driving motor 30 are driven. When the value ofthe counter reaches 100, namely, 100 ms have passed, the driving of therear lens group driving motor 30 is stopped and only the whole unitdriving motor 25 is driven continuously. Since the above processes arerepeated, during the driving of the whole unit driving motor 25, therear lens group driving motor 30 is driven for 20 ms in each 100 msperiod.

If the housed code is not detected before the time of the four-secondtimer expires, the time is judged to expire at step S1337 The housedcode will not be detected within four seconds if the movement of thelens is obstructed for some reason, and in such a case, at steps S1339and S1341, the rear lens group driving motor 30 and the whole unitdriving motor 25 are stopped, and the process is ended upon setting theerror flag to 1 to indicate the occurrence of an error.

During the above process, when the housed code is detected, the CPU 210stops the rear lens group driving motor 30 at step S1363, and furtherstops the whole unit driving motor 25 at step S1365, and after closingthe barrier by calling the barrier closing process, the lens housingprocess is completed. The barrier closing process is the process toclose the lens barrier by the rear lens group driving motor 30.

[The Lens Extension Process]

FIG. 46 shows a flow chart of the lens extension process. In the lensextension process, when the state of the camera changes from being inthe standby state to the power "ON" state (i.e., the operational state),the lens barrier is opened and the lenses (i.e., the front lens group L1and the rear lens group L2) are extended from the housed position to the"wide" end position.

When the lens extension process is called, at step S1401, the barrieropening process is called and the barrier is opened by driving the rearlens group driving motor 30. In the barrier opening process, if a pulseis not output from the AF reference pulse input circuit 222, namely, ifthe rear lens group driving motor 30 is not driven, the error flag isset to 1.

At step S1403, it is judged whether the error flag has been set to 1 inthe barrier opening process. The error flag will be set to 1 if thebarrier opening process does not end normally, and in this case, thelens extension processes after step S1405 are not executed and controlreturns. The error flag will be set to 0 if the barrier opening processis ended normally, and in this case, at step S1405 the whole unitdriving motor 25 is driven clockwise and the movement of the rear lensgroup L2 and the front lens group L1 in the "tele" direction is started.

With the commencement of driving of the whole unit driving motor 25, theCPU 210 starts the four-second timer at step S1407, and monitors whetherthe "wide" end code (i.e., whether the lenses reach the "wide" endposition) is detected before the time of the timer expires.

At step S1409, the CPU 210 judges whether timer has expired. Normally,since the lenses reach the "wide" end position within four seconds fromstarting of the lens extension, the judgement at step S1409 is "N". Atstep S1415 the zoom code input process is called, and at step S1417 itis judged whether the input code, namely, the zoom code corresponding tothe lens position, is the "tele" end code, and if the input code is notthe "tele" end code, at step S1419 it is judged whether the input codeis the "wide" end code.

Under normal conditions, the lens moves from the housed position to the"tele" end position within four seconds. Accordingly, before the time ofthe four-second timer expires, if neither the "tele" end code nor the"wide" end code is detected, it represents, for example, that themovement of the lens is obstructed. Therefore, if at step S1409 the timeis judged to expire during the lens movement, at step S1411 the drivingof the whole unit driving motor 25 is stopped, and at step S1413 theerror flag is set to indicate that an error has occurred, and the lensextension process is ended.

In the normal lens extension process, when the lenses are extended, the"wide" end code is firstly detected. At step S1419, if the "wide" endcode is detected, then at step S1423 the zoom step, which is anindicator of the lens position, is set to 0, corresponding to the "wide"position. From step S1425, the processes for stopping the lenses areexecuted.

If the lens extension process is continued without detecting the "wide"end code, the lenses will eventually reach the end of the range ofcapable movement, and will become immovable. In the camera 1 of thepresent embodiment, during the lens extension process, the lenses willcontinue to move even without the "wide" end being detected, and whenthe "tele" end code is detected at step S1417, the movement of thelenses, namely, the processes after step S1425, will be stopped. Whenthe lenses reach the "tele" end position, the zoom step is set to 13,corresponding to the "tele" end position, at step S1421. Therefore,during the lens extension process, the zoom step will be set to thecorrect value corresponding to the lens position even when the lenseshave moved to the "tele" end.

As described above, when the lenses have been extended and the zoom stephas been set to correspond to the lens position, from steps S1425 toS1435 the processes to stop the lenses are executed. In the camera ofthe present embodiment, in order to obtain the position of the lens, thezoom step is set upon detecting the zoom code. When the lenses arestopped, for the purpose of detecting the zoom code, the brush 9a isdesigned so as to stop at a position that is shifted towards the "wide"end position by a predetermined amount, namely, "the standby position".When the lenses are moved for the purpose of zooming or focusing, thelenses are moved once towards the "tele" side, regardless of whether thedirection of movement is towards the "wide" end or the "tele" end, inorder for the brush 9a to contact the zoom code. The zoom code is theninput to the CPU 210, which then controls the amount of movement of thezoom lens based on the position at which the zoom code is input, i.e.,by making the position at which the zoom code is input a referenceposition.

At step S1425, a first zoom pulse ZP1 having a predetermined value, isset in the zoom pulse counter and the zoom driving process is called, asshown in FIG. 57. In the zoom driving process, the whole unit drivingmotor 25 is driven clockwise, namely, in the direction in which thelenses are moved toward the "tele" side, until the number of pulsesoutput to the CPU 210 by the zoom pulse input circuit 220 (output insynchronization with the rotation of the whole unit driving motor 25),becomes equal to the value of the counter value set in the zoom pulsecounter. Thus, the lenses will be stopped upon being moved furthertowards the "tele" position by a predetermined amount from the positionat which the zoom code detecting terminal detects the zoom code.

The value by which the brush for zoom code detection will be moved pastthe zoom code and positioned at a non-continuous part on the "tele" sidewhen the lenses are moved by the zoom driving process, is used as thefirst zoom pulse ZP1, which is set at the zoom pulse counter at stepS1425. The value of the first zoom pulse ZP1 also satisfies thefollowing conditions. In the camera of the present embodiment, themagnification of the finder optical system varies according to themovement of the lenses. Accordingly, the first zoom pulse ZP1 is set sothat the magnification of the finder will not be affected even if thelenses are moved by an amount corresponding to this value of the pulse.In the present embodiment, though the lenses move when the shutterbutton is pressed, the number of zoom pulses, corresponding to theamount of movement of the lenses at that time, is set to a value whichwill not exceed that of the first zoom pulse ZP1.

After the lenses are moved by an amount corresponding to the zoom pulseZP1, at step S1429 it is judged whether the rear lens group L2 ispositioned at the AF home position, and if the rear lens group L2 is notpositioned at the AF home position, namely, if the rear lens group L2 isextended from the AF home position at step S1429, the AF return processis called at step S1431 and the rear lens group L2 is moved to the AFhome position. With the rear lens group L2 being positioned at the AFhome position, the AF two-stage extension process at step S1433, and thezoom return process at step S1435, are executed and control returns tothe calling routine.

The AF two-stage extension process is the process in which the rear lensgroup L2 is extended by a certain amount from the AF home position. Inthe camera of the present invention, when photography is performed(i.e., when the shutter button is fully depressed), after the front lensgroup L1 and the rear lens group L2 have been moved simultaneously forzooming, in addition to the movement of the front lens group L1 and therear lens group L2 by the whole unit driving motor 25, the movement ofonly the rear lens group L2 by the rear lens group driving motor 30 isalso performed for the purpose of focusing and adjustment of the focallength.

During photographing, since the amount of movement of the rear lensgroup L2 is relatively large when the lenses are at the "wide" end side,the release time lag, which is the time difference between the point atwhich the shutter button is pressed and the point at which exposure isactually performed, becomes rather long. In order to shorten the releasetime lag, in the camera of the present invention, when the lenses arepositioned at the "wide" side (the movement of the rear lens group L2 isrelatively large), the rear lens group L2 is extended by a predeterminedamount in advance. The AF two-stage extension process of step S1433 isperformed for this purpose, and is the process by which the rear lensgroup L2 is extended by a predetermined amount, only when the lenses arepositioned on the "wide" side. In the present embodiment, the judgementas to whether the lenses are on "wide" side, is made according towhether the zoom step is less than or equal to 4, will be describedlater (see below). In step S1435, the zoom return process moves thelenses toward the "wide" direction by a predetermined amountcorresponding to zoom pulse ZP2 (described hereinafter).

[The Zoom "tele" Movement Process]

FIG. 47 shows a flow chart of the zoom "tele" movement process. Thisprocess will be described with reference to FIG. 34, which shows therelationship between the zoom code plate 13b and the positions of thefront lens group L1 and the rear lens group during the zoom "tele"movement process. The zoom "tele" movement process is a process to drivethe whole unit moving motor 25 in a direction in which the lens barrels16, 19 and 20 extend (i.e., in the direction in which the focal lengthis made long), namely the front lens group L1 and the rear lens group L2are advanced as a whole without changing the relative distancetherebetween.

In the zoom "tele" movement process, the zoom code corresponding to thepresent position of the lens is detected by driving the whole unitdriving motor 25 clockwise. The point at which the zoom code turns "ON"is used as a reference point when the whole unit driving motor 25 is tobe stopped. After the whole unit moving motor 25 is driven clockwise toadvance the lenses by the predetermined first zoom pulse value ZP1 withrespect to this reference point, the whole unit driving motor 25 isdriven counterclockwise. After the whole unit driving motor 25 has beendriven to rotate counterclockwise by the second zoom pulse value ZP2with respect to the point at which the zoom code turns "ON/OFF" again,the whole unit driving motor 25 is driven clockwise by a backlasheliminating zoom pulse value ZP3, and the whole unit driving motor 25 isstopped. By this zoom "tele" movement process, the zoom lens is stoppedbetween zoom codes with backlash in the forwarding (advancing) directionbeing removed to some extent.

Furthermore, in the present embodiment, when the whole unit drivingmotor 25 stops, if the zoom step is not more than 4, the rear lens groupL2 is retracted by an amount corresponding to the predetermined AF pulsevalue AP1. In the present embodiment, the present lens position iscontrolled by dividing the focal length range, from the "wide" end tothe "tele" end, into fourteen parts, and assigning the zoom step 0 tothe "wide"end, the zoom step 13 to the "tele" end, and zoom steps 1through 12 to the focal lengths in between.

In the zoom "tele" movement process, at step S1501 it is checked whetherthe lenses are at the "tele" end position, and if the lenses are at the"tele" end position, control returns since there is no need fortele-zooming.

If the lenses are not at the "tele" end position at step S1501, at stepS1503 the whole unit driving motor 25 is driven clockwise, namely, inthe tele-zoom direction, and the zoom code, input process is executed atstep S1505. The process waits until the present zoom code correspondingto the zoom step is detected at step S1507. When the present zoom codecorresponding to the zoom step is detected, at step S1509 a two-secondtimer is started to detect a state in which the whole unit driving motor25 is incapable of driving for a predetermined period of time (i.e., twoseconds).

When the two-second timer is started, at step S1511 it is checkedwhether the time has expired. In the case of normal operations the timewill not be up, and therefore at step S1513 the zoom code input processis executed. Then at step S1515 it is checked whether the zoom code haschanged, and if the zoom code has not changed, a "tele" end codedetecting check is directly executed at step S1519. If the zoom code haschanged, the "tele" end code detecting check is executed at step S1519only after restarting the two-second timer at step S1517.

If the zoom code does not change even after the whole unit driving motor25 has driven for the predetermined period of time, it is assumed thatan abnormal condition, such as the lens barrel has contacted someobject, has occurred. Therefore at steps S1511, S1537 and S1539, afterstarting the two-second timer, if the two seconds have elapsed and thetime of the two-second timer expires without any variation of the zoomcode, the whole unit driving motor 25 is stopped, the error flag is set,and control is returned.

If the "tele" end code is not detected at step S1519, it is judgedwhether the next zoom code is detected at step S1521, and if the nextcode is not detected, the processes of steps S1511 through S1519 arerepeated. Upon detection of the next zoom code, the zoom step isincremented by 1 at step S5123, and if the "tele" switch 62T is ON atstep S1525, control is returned to step S1511 and the above processesare repeated, while if the "tele" switch is OFF, a jump to step S1525 isperformed. That is, once this process is entered, tele-zooming isperformed by one zoom step even when the zoom switch 62T is turned OFFbefore tele-zooming is performed by one zoom step.

A jump to step S1529 is performed when the lenses reach the "tele" endor when the "tele" switch 62T is turned OFF (steps S1525, S1529 orS1519, S1527, S1529). If the jump is performed upon reaching the "tele"end, the zoom step is set to 13, at step S1527.

At step S1529, the predetermined first zoom pulse value ZP1 is set inthe zoom pulse counter. Then after the zoom driving process at stepS1531, the AF two-stage delivery process (step S1533) and the zoomreturn process (step S1535) are executed, and control is returned.

In the zoom driving process, the whole unit driving motor 25 is drivenclockwise (i.e., in the direction in which the lenses are extended) byan amount corresponding to the value of the zoom pulse counter, namely,that of the first zoom pulse value ZP1.

In the AF two-stage extension process, when the whole unit driving motor25 is stopped, if the zoom step is not more than 4, the rear lens groupL2 is retracted by an amount corresponding to the predetermined AF pulsevalue (i.e., AP1). Then the whole unit driving motor 25 is drivencounterclockwise, by an amount corresponding to the second zoom pulsevalue ZP2, with respect to the point at which the zoom code turnsON/OFF. Then the whole unit driving motor 25 is driven clockwise by anamount corresponding to the backlash eliminating third zoom pulse valueZP3, and the whole unit driving motor 25 is stopped. By this zoom "tele"movement process, the zoom lens is stopped between zoom codes with thebacklash in the advancing direction being somewhat eliminated.

In the zoom return process, the whole unit driving motor 25 is drivencounterclockwise, and is further driven counterclockwise by an amountcorresponding to the second zoom pulse value ZP2 with respect to thepoint at which the zoom code turns ON/OFF. After that, the motor isdriven clockwise by an amount corresponding to the backlash eliminatingthird zoom pulse value ZP3, and then the whole unit driving motor 25, isstopped to stop the front lens group L1 and the rear lens group L2 atthe standby position between the zoom codes.

[The Zoom "wide" Movement Process]

FIG. 48 shows a flow chart for the zoom "wide" movement process. Thisprocess shall be firstly described with reference to FIG. 34, whichshows the relationship between the zoom code plate 13b and the positionsof the front lens group L1 and the rear lens group L2 during the zoom"wide" movement process. In the zoom "wide" movement process the wholeunit driving motor 25 is driven in the direction in which the lensbarrels 16, 19 and 20 are retracted (i.e., the direction in which thefocal length is made shorter), namely, the front lens group L1 and therear lens group L2 are retracted as a whole without changing thedistance therebetween.

In the zoom "wide" movement process, the whole unit driving motor 25 isdriven clockwise and after being driven clockwise further by an amountcorresponding to the first zoom pulse value ZP1. From the point at whichthe zoom code corresponding to the present lens position is detected,the whole unit driving motor 25 is driven counterclockwise. When thewhole unit driving motor 25 is stopped in the intermediate zoom region,the motor 25 is further driven counterclockwise by an amountcorresponding to the second zoom pulse value ZP2 from the point at whichthe zoom code turns "ON/OFF". Then the motor 25 is drivencounterclockwise by an amount corresponding to the backlash eliminatingzoom pulse value ZP3, and then the whole unit driving motor 25, isstopped. By this zoom "wide" movement process, the zoom lens is stoppedbetween zoom codes with the backlash in the forwarding (advancing)direction being somewhat eliminated.

In the present embodiment, when the whole unit driving motor stops, ifthe zoom step is not more than 4, the rear lens group L2 is retracted byan amount corresponding to the predetermined AF pulse value AP1. Themotor 25 is then driven counterclockwise by an amount corresponding tothe second zoom pulse value ZP2 with respect to the point at which thezoom code turns "ON/OFF", and then the motor 25 is driven clockwise byan amount corresponding to the zoom pulse value ZP3 for backlashelimination, and then the whole unit driving motor 25 is stopped. Bythis zoom "wide" movement process, the zoom lens is stopped between zoomcodes with the backlash in the advancing direction being eliminated tosome extent.

When the zoom "wide" movement process is entered, at step S1601 it ischecked whether the lens is at the "wide" (i.e., "wide" end) position,and if the lens is at the "wide" position, control returns since thereis no need for zooming.

If at step S1601, the lens is not at the "wide" position, the whole unitdriving motor 25 is driven in a clockwise direction, i.e., tele-zoomingdirection, at step S1603 since there is a possibility that the lensesmay have been moved past the next zoom code due to the backlash when thelenses were retracted. At step S1605 the zoom code input process isexecuted and the process waits until the present zoom code correspondingto the zoom step is detected at step S1607. When the present zoom codecorresponding to the zoom step is detected, the whole unit driving motoris stopped (step S1609), driven counterclockwise (step S1611), and thetwo-second timer is started at step S1613.

When the two-second timer is started, it is checked whether the timeexpires at step S1615. In the case of normal operations the time willnot be up, and therefore at step S1617 the zoom code input process isexecuted. It is then checked whether the zoom code has changed at stepS1619, and if the zoom code has changed, the two-second timer isrestarted (step S1621) and it is checked whether the housed code hasbeen detected at step S1623. If the zoom code has not changed at stepS1619, control proceeds to step S1623. If the housed code is notdetected at step S1623, it is checked whether the "wide" end code isdetected at step 51625, and if the "wide" end code is also not detected,it is checked whether the next zoom code has been detected at stepS1627. If the next zoom code has not been detected, control returns tostep S1615, and the process from steps S1615 to S1627 are repeated untilthe next zoom code is detected.

When the next zoom code is detected at step S1627, the zoom step isdecremented by 1 at step S1629, and if the "wide" switch 62W is ON atstep S1631, control returns to step S1615 and the above processes ofsteps S1615 through S1631 are repeated. If the "wide" end code isdetected at step S1625, or if the "wide" switch is OFF, control jumps tostep S1633 and the zoom return process is called (steps S1625, S1633,S1635, S1637 or S1631, S1635, S1637). At step S1637, when the jump isperformed upon detection of the "wide" end code, the zoom step is set to0.

In the zoom return process at step S1633, the front lens group L1 andthe rear lens group L2 are returned to the standby position at whichthey were positioned before the lens driving process during thephotographing process.

In the AF two-stage delivery extension at step S1635, the rear lensgroup L2 is retracted to the AF home position, or to the positionretracted from the AF home position by an amount corresponding to thevalue AP1 in accordance with the present zoom step.

Although the above description is directed to a normal operation, incases where the lens barrel is forcibly pushed etc., it is checked atstep S1623 that the housed code has been detected. If so, the whole unitdriving motor 25 is stopped at step S1639, and the lens extensionprocess is executed at step S1641 before the control is returned. Inaddition, if two-second timer expires, for example when the lens barrelis pressed and is incapable of movement, the whole unit driving motor 25is stopped at step S1645, and control returns after setting the errorflag to 1.

In the present zoom "wide" process, since the "wide" switch check isexecuted after detecting the present zoom code and the next zoom code,wide zooming is performed by one zoom step once this process is entered,even when the zoom "wide" switch 62W is OFF before zooming is performedby one step.

[The Photographing Process]

FIG. 49 shows a flow chart for the photographing process. Thephotographing process, of the present embodiment, is called when thephotometering switch SWS is turned ON, and is characterized in that itis checked if the front lens group L1 is at the standby position. Thefront lens group L1 and the rear lens group L2 are moved to positions atwhich the subject will be in focus, in accordance with the preset focallength after the release switch SWR is turned ON.

In the photographing process, at step S1701, the zoom standbyconfirmation process is executed, and the front lens group L1 is movedto the standby position corresponding to the present focal length.

Then at steps S1703, S1705 and S1707, the object distance measuringprocess is executed and the focal length is obtained, the photometeringprocess is executed and the luminance of the subject is obtained. The AEcalculation process is also executed to determine the shutter speed, theaperture value, and whether strobe flashing is necessary. Strobeflashing will be necessary when the luminance of the subject is at thestrobe flashing level in the auto strobe flashing mode, or when theforced strobe flashing mode is set, etc. If it is judged that strobeflashing is necessary at step S1709, the photographing charging processis executed at step S1711. During the photographing charging process, ifthe photometering switch SWS is turned OFF or if the time of thecharging timer expires (step S1713), control returns, while ifsufficient charging has been completed, after executing the flashmatic(FM) operation at step S1715, control proceeds to step S1717. If strobeflashing is not necessary at step S1709, control proceeds to step S1717,skipping steps S1711 through S1715.

At step S1717, it is checked whether the photometering switch SWS isturned ON, and if the photometering switch SWS is turned OFF, controlreturns. If the photometering switch SWS is ON at step S1717, theprocess waits for the release switch SWR to be turned ON (step S1719)while the photometering switch SWS remains ON.

When the release switch SWR is ON (step S1719) and if the self-timermode is not set at step S1721, the lens drive calculation process isexecuted at step S1725. If the self-timer mode is set, the lens drivecalculation process is executed after a self-waiting process at stepS1723, in which the process waits for a predetermined duration of time.

In the lens drive calculation process, the amount of movement, i.e., thezoom pulse value, of the front lens group L1 with respect to the ON/OFFswitching point of the zoom code and the amount of movement, i.e., theAF pulse value, of the rear lens group L2 with respect to the switchingpoint of the AF home signal (AF home position) are calculated accordingto the result of focusing and the present focal length.

Then at steps S1725 and S1727, according to the amount of movement ofthe front lens group L1 and the rear lens group L2 obtained through thelens drive calculation process, the lens driving process is executed. Inthe lens driving process, the rear lens group L2 is driven together withthe front lens group L1, and control is performed to bring the subjectinto focus.

When the movement of the lens is completed, at step S1729 the green lamp228 is lit (i.e., current is passed through the green lamp) to notifythe photographer that the shutter will be released, and the exposureprocess is executed at step S1731. The green lamp 228 only stays lit fora small duration of time and then is turned OFF.

After the exposure process has completed, at step S1733, the lens returnprocess is executed, in which the front lens group L1 and the rear lensgroup L2 are returned to the positions they were at prior to movement atstep S1727.

Then at steps S1735, S1737 and S1739, the film winding process isexecuted, and if the film is not at the end, control is returned, whileif the end of the film has been reached, the rewinding process isexecuted and control returns.

[The Main Charging Process]

FIG. 50 shows a flow chart for the main charging process. The maincharging process is the charging process that is called in the mainprocess (FIG. 41) when the charging demand flag equals 1.

At step S1801, the CPU 210 judges whether the value of the chargedisable timer is set to 0. The charge disable timer is a timer in whichthe time to disabled charging is set. A charge disable time of threeseconds is set when the flash capacitor 530 of the strobe device 231 isfully charged. If the time has not expired at the charge disable timerat step S1801, at step S1803 the charging demand flag is set to 0, andthe process is ended. In such a manner, while the charge disable timeris counting the three seconds during which charging is to be disabled,the CPU 210 prohibits charging unconditionally without checking thecharging voltage. The charging can be interrupted (disabled) by settingthe level of the terminal CHEN of the strobe device 231 to L.

If the time at the charge disable timer expires, at step S1805 the CPU210 judges whether the charge interruption flag is set to 1. As will bedescribed later, the charge interruption flag is set to 1 when thecharging process is canceled before the completion thereof. In thepresent main charging process and in the photographing charging process,which will be described later, the charging process is deemed to havebeen completed normally when the charging voltage reaches apredetermined value, or when the charging time reaches a predeterminedtime (for example, in the present camera, eight seconds). Duringcharging, if the charging is interrupted due to the operation of anotherswitch, etc., the time spent on charging prior to interruption isdeducted from the predetermined time, namely from eight seconds, and theremaining time is stored in the memory. When charging is resumed, it isjudged whether the charging voltage will reach the predetermined valuewithin the remaining time.

Therefore, if the charge interruption flag is set to 1 the chargeinterruption flag is cleared (i.e., set to 0), and a resumed chargingprocess is performed by setting the charging timer to the remaining timewhich has been stored in the memory. If the charge interruption flag isnot 1, namely if the charging process has not been interrupted at stepS1805, charging is performed upon setting the charging timer to thepredetermined charging, i.e., eight seconds.

In order to start charging, the CPU 210 turns ON the charging signal atstep S1813. In other words, charging is started by setting the level ofterminal CHEN of the strobe device 231 to be high (H). While the levelat the terminal CHEN on the strobe device 231 is H, an A/D conversion isperformed on the output of terminal RLS of the strobe device 231, andthe converted output is input to the CPU 210. At step S1815, the CPU 210checks the charging voltage based on the A/D converted voltage value. Ifthe charging voltage has reached the upper limit at step S1817, then atstep S1819, the CPU 210 disables charging for three seconds, by settingthree seconds as the charge disable time in the charge disable timer,and then at step S1821, the CPU 210 stops the charging by making thevoltage at the terminal CHEN of the strobe device 231 as low (L). Thenthe charging demand flag is set to 0 at step S1823 and the main chargingprocess is completed.

If at step S1817, the CPU judges that the charging voltage has notreached the upper limit, at step S1825 it is judged whether chargingtimer has expired. If the charging timer expires, at step S1821 thecharging is stopped by making the level at the terminal CHEN of thestrobe device 231 as L, and at step S1823 the charging demand flag isset to 0 to indicate the completion of the charging process. Forreference, if the main charging process is completed after the time ofthe charging timer expires, the charge disable time of three seconds isnot set.

If the time of the charging timer has not expired at step S1825, then atstep S1827, the CPU judges whether the state of any of the switches haschanged. If any change of state amongst the switches is detected, thecharging process is interrupted, and the process corresponding to theoperated switch is performed in accordance with a predeterminedpriority. Therefore, upon detecting a change in the state of theswitches, the CPU 210 sets the charging signal to OFF at step S1829(i.e., sets the level at the terminal CHEN of the strobe device 231 tobe low). At step S1831 the remaining time indicated by the chargingtimer is stored in the memory, and at step S1835 the charge interruptionflag is set 1 to indicate the interruption of charging, and the maincharging process is completed. The remaining time stored in the memoryat step S1831, and the charge interruption flag set at step S1835, arereferred to at the time of execution of the next main charging processor the next photographing charging process.

[The Shutter Initialization Process]

FIG. 51 shows a flow chart for the shutter initialization process. Inthe shutter initialization process of the present embodiment, the AEmotor 29, which drives the shutter 27, is driven in the shutter closingdirection to fully close the shutter blades until the shutter bladescome into contact with the stoppers.

At step S1901, the AE motor 29 is firstly driven counterclockwise todrive the shutter blades 27a in the closing direction. Then at stepS1903 the AE pulse counting limit timer is started, and the AE pulsecount process is called to wait for the time to expire at the AE pulsecounting limit timer, while detecting the AE pulse (steps S1905, S1907).The AE pulse counting process is performed by the CPU 210 in combinationwith the AE pulse inputting circuit 221.

At steps S1907 and S1909, the shutter blades 27a are completely shut andthe AE motor 29 becomes incapable of driving, since the time will haveexpired as determined by the AE pulse counting limit timer, the AE motor29 is released, and control is returned.

By the above process, the shutter 27 is set to the initial position atwhich the shutter blades 27a are completely shut.

[The Zoom Code Input Process]

FIG. 52 shows a flow chart of the zoom code input process. In the zoomcode input process, the zoom code is set based on the A/D convertedvalue of the voltage input into the A/D conversion terminal of the CPU210 from the zoom code information input circuit 219.

At step S3201, a voltage is input from the zoom code information inputcircuit 219 into the A/D terminal of the CPU 210. The CPU 210 comparesthe A/D converted value of the input voltage with the threshold voltagesVa through Vf, and sets the zoom code corresponding to the inputvoltage. The setting of the zoom code is executed as follows.

At step S3203, the CPU 210 compares the A/D converted value with thethreshold voltage Va. If the A/D converted value of the input voltage isgreater than the threshold voltage Va at step S3203, the zoom code isset to 0 at step S3205, and control is returned.

If the A/D converted value of the input voltage is less than or equal toVa at step S3203, and greater than Vb at step S3207, the zoom code isset to 5 at step S3209.

If the A/D converted value of the input voltage is less than or equal toVb at step S3207, and greater than Vc at step S3211, the zoom code isset to 4 at step S3213.

If the A/D converted value of the input voltage is less than or equal toVc at step S3211, and greater than Vd at step S3215, the zoom code isset to 3 at step S3217.

If the A/D converted value of the input voltage is less than or equal toVd at step S3215, and greater than Ve at step S3219, the zoom code isset to 6 at step S3221.

If the A/D converted value of the input voltage is less than or equal toVe at step S3219, and greater than Vf at step S3223, the zoom code isset to 1 at step S3225.

If the A/D converted value of the input voltage is less than or equal toVf at step S3223, the zoom code is set to 2 at step S3227.

Here, the codes identified by Vd, Ve and Vf, for:which the, intervalbetween the threshold voltages is relatively large, are respectivelyassigned to the lens housed position (the zoom code=1), the "wide" endposition (the zoom code=2) and the "tele" end position (the zoomcode=6), which become reference points for the lens position. In such amanner, the correct zoom code will be set at least for the referencepoints even if the voltage input into the CPU 210 varies somewhat due tovoltage fluctuations.

[The AF Pulse Confirmation Process]

FIG. 53 shows a flow chart for the AF pulse confirmation process. In theAF pulse confirmation process the rear lens group driving motor 30 isdriven alternately in the clockwise and counterclockwise directions. Forexample, during driving of the rear lens group driving motor 30, if therear lens group driving motor 30 is unable to rotate for some reason, byalternately driving the rear lens group driving motor 30 clockwise andcounterclockwise, the cause of the obstruction of rotation of the rearlens group driving motor 30 may be removed, thus allowing the rear lensgroup L2 to move. In the present embodiment, the rear lens group drivingmotor 30 alternately rotates clockwise and counterclockwise, and afterconfirming that the rear lens group driving motor 30 has rotated morethan a predetermined amount, the rear lens group L2 is moved to the AFhome position. If this confirmation has not been made within fiveoperations of alternate clockwise and counterclockwise driving, or evenif such a confirmation is made, if the rear lens group L2 does not moveto the AF home position within the predetermined time, the rear lensgroup driving motor 30 is stopped, and the error flag is set to 1.

At step S3301, the value of the counter which defines the maximum numberof times that the rear lens group driving motor 30 is driven alternatelyin the clockwise and counterclockwise directions is set to 5.

Then at steps S3303, S3305 and S3307, the rear lens group driving motor30 is firstly driven clockwise, namely in the direction in which therear lens group is retracted, the AF pulse counting process is performedupon setting the value of the AF pulse counter to 50, and the processwaits until 50 AF pulses are output. When the value of the AF pulsecounter becomes 50, at step S3309 the rear lens group driving motor 30is stopped.

At step S3311 it is checked whether the OK flag is set, and if the OKflag is set, in other words if 50 AF pulses have been output, it ischecked whether the rear lens group L2 is at the AF home position. Ifthe rear lens group L2 is at the AF home position, control returns,while if the rear lens group L2 is not at the AF home position, at stepS3331 and step S3335 the rear lens group driving motor 30 is drivencounterclockwise, namely in the direction in which the rear lens groupL2 is moved towards the AF home position, and a 500 ms timer is started.Since the rear lens group L2 will normally reach the AF home positionbefore the time of the 500 ms timer expires, the rear lens group drivingmotor 30 is stopped and control is returned when the rear lens group L2reaches the AF home position (steps S3335, S3337, S3339). If the rearlens group L2 does not reach the AF home position before the time of the500 ms timer expires at S3335, at steps S3335, S3341 and S3343, the rearlens group driving motor 30 is stopped, and control is returned uponsetting the error flag to 1.

Although the above is directed to a normal case, if the rear lens groupL2 does not move easily the following processes are executed.

In the AF pulse counting process at step S3307, if the AF pulse is notoutput for a predetermined amount of time even though the rear lensgroup driving motor 30 is being driven, this probably will indicate thata condition is occurring in which the rear lens group driving motor 30cannot move due to biting, etc., therefore, the OK flag is cleared. Inthis case, control proceeds to the rolling process, from steps S3311 toS3313. When control is at step S3313, after waiting for 100 ms, the rearlens group driving motor 30 is driven counterclockwise at step S3315.Then at steps S3317, S3319 and S3321, the value of the AF pulse counteris set to 50, the AF pulse counting process is executed, and then therear lens group driving motor 30 is stopped. In the AF pulse countingprocess, when 50 AF pulses are detected, the OK flag is set, and if 50AF pulses are not detected within a predetermined time, the OK flag iscleared. Thus, if the rear lens group L2 moves during such acounterclockwise rotation of the rear lens group driving motor 30,control proceeds to the process at step S3329, while if the rear lensgroup L2 does not move, control proceeds to the process at step S3325.

At step S3325, the counter is decremented by one, and if the value ofthe counter is not 0, control returns to step S3303, and the processesfrom step S3303 are repeated. If the value of the counter becomes 0,namely if the rear lens group L2 is not moved even upon repeating theclockwise and counterclockwise driving of the rear lens group drivingmotor 30 five times, since this will indicate that some form of troublemay be occurring with the lens driving system. At steps S3341 and S3343,the rear lens group driving motor 30 is stopped, and the error flag isset to 1 and control is returned.

[The AF Return Process]

FIG. 54 shows a flow chart for the AF return process. In the AF returnprocess the rear lens group L2 is returned to the AF home position. Atsteps S3401 and S3403, the rear lens group driving motor 30 is drivencounterclockwise, namely in the direction in which the rear lens groupis advanced, to advance the rear lens group L2 towards the AF homeposition and the process waits until the rear lens group L2 reaches theAF home position.

At steps S3405, S3407, S3409, S3411 and S3413, when the arrival of therear lens group L2 at the AF home position is detected, via thephotointerrupter 301, the driving of the rear lens group driving motor30 is switched to low-speed counterclockwise driving, and a value of 10is set in the counter. The rise of the AF pulse is then counted and thecounter is decremented by one on each count and the process waits untilthe value at the counter becomes 0.

At steps S3413 and S3415, when the value at the counter becomes 0, therear lens group driving motor 30 is stopped, and control is returned. Insuch a manner, the rear lens group L2 is stopped at the AF homeposition.

In the present embodiment, after the rear lens group L2 reaches the AFhome position, the driving of the rear lens group driving motor 30 iscontinued for another ten pulses. This is done since the driving pulsecount for the rear lens group L2 is based on the switching of the AFhome signal and so that the rear lens group L2 will definitely be at theAF home position in the standby condition.

[The Barrier Closing Process]

FIG. 55 shows a flow chart for the barrier closing process. In thebarrier closing process the barrier is closed upon housing of thelenses.

Firstly, a value 3, which is the number of times the opening/closingprocess (described later) is to be repeated when a fault occurs, is setin the counter. In the present embodiment, the judgement whether thebarrier closing process is completed normally, is made according towhether the rear lens group driving motor 30 has driven clockwise by apredetermined amount, namely, whether a predetermined number of AFpulses have been counted upon driving the rear lens group driving motor30.

During clockwise driving of the rear lens group driving motor 30, if thepredetermined number of AF pulses is not input from the AF referencepulse inputting circuit 222, it can be suspected that the barrier couldnot be closed due to some reason, or that the barrier closing processwas executed with the barrier closed already.

Therefore, in the present embodiment, when the predetermined number ofAF pulses is not counted upon clockwise driving of the rear lens groupdriving motor 30, the rear lens group driving motor 30 is once drivencounterclockwise by a predetermined amount, namely by an amountsufficient for opening the closed barrier, and then the rear lens groupdriving motor 30 is driven clockwise again. The number of times set atstep S3501 is the value for restricting the number of times of executionof the process in which the rear lens group driving motor 30 is oncedriven counterclockwise and then driven clockwise again (describedabove)

At step S3503, the rear lens group driving motor is driven clockwise,namely, driven in the direction by which the barrier will close, and atstep S3505 a value of 300 is set in the AF pulse counter, and at stepS3507 the AF pulse counting process is called. In the AF pulse countingprocess the AF pulse counter, set at step S3505, is decremented based onthe pulse signals output to the CPU 210 from the AF reference pulseinput circuit 222 in synchronization with the rotation of the rear lensgroup driving motor 30.

The AF pulse counting process is ended when the pulse is not outputwithin a predetermined time, or when the count value at the decrementedAF pulse counter becomes 0.

After completion of the AF pulse counting process, at step S3509 therear lens group driving motor 30 is stopped, and at step S3511, it isjudged whether the AF pulse count remaining after being decremented inthe AF pulse counting process is less than 100.

At step S3511, if the value of the AF pulse counter is less than 100,namely, if the value was decremented by 200 or more in the AF pulsecounting process, it is judged that the barrier was closed normally, andthe barrier closing process is ended. If the value of the AF pulsecounter is 100 or more at step S3511, it is considered that the rearlens group driving motor 30 cannot rotate due to some reason, and theelimination of the obstruction is attempted by once rotating the rearlens group driving motor 30 once counterclockwise, and then againclockwise. In such a manner, the obstacle can be removed.

The control proceeds to step S3519, as long as the counter value doesnot become zero upon decrementing of the counter at step S3513. At stepS3519, the rear lens group driving motor 30 is driven counterclockwise,and a value of 300 is set in the AF pulse counter, and the AF pulsecounting process is called. After completion of the AF pulse countingprocess at step S3523, the rear lens group driving motor 30 is stoppedat step S3525, and the control returns to step S3503. Then at stepsS3503, S3505, S3507 and S3509, the clockwise driving of the rear lensgroup driving motor 30, the setting of the AF pulse counter, theexecution of the AF pulse counting process, and stopping of the rearlens group driving motor 30 are made. It is then judged at step S3511,whether the barrier has closed, based on the value of the AF pulsecounter. In the present embodiment, since a value of 3 is set at thecounter at step S3501, if the barrier is not closed, the above retryprocess is repeated twice.

During the above process, if the barrier closes, at step S3511 the valueof the AF pulse counter will be less than 100, and the barrier closingprocess is completed. In addition, after repeating the process, if thevalue of the AF pulse counter does not become less than 100, after thelast of the repetitions, the barrier is judged not to be closed, and thebarrier closing process is ended upon setting the error flag to 1 toindicate an occurrence of a fault.

[The Barrier Opening Process]

FIG. 56 shows a flow chart for the barrier opening process. In thebarrier opening process the barrier is opened when the lenses areextended from the housed position.

First, a value of 3, which is the number of times of repetition of theprocess, is set at the counter at step S3601. Normally, the barrieropening process; is called with the barrier being closed. However, thebarrier opening process will be executed with the barrier open when, forexample, the battery of the camera is changed with the lens beingextended, i.e., the barrier is open. The barrier opening process mayalso be called when the lenses are housed without the barrier beingclosed because of some obstruction. If the rear lens group driving motor30 is driven to open the barrier when the barrier is already open, therear lens group driving motor 30 will not rotate because the barrier isopen, and the AF reference pulse input circuit 222 will therefore notgenerate any pulses.

Therefore, in the present process, the rear lens group driving motor 30is driven in order to open the barrier, and if the opening of thebarrier is not confirmed, in other words, if the AF reference pulseinput circuit 222 does not output pulses to the CPU 210, the rear lensgroup driving motor 30 is driven in the direction to close the barrier,and is again driven in the direction to open the barrier. The number oftimes set at the counter at step S3601 is the value for restricting thenumber of times of execution of the above-described process in which thebarrier is opened after closing, which is executed when it cannot beconfirmed that the barrier was opened upon driving the rear lens groupdriving motor 30 for the first time.

At step S3603, the rear lens group driving motor is drivencounterclockwise, namely, in the direction in which the barrier opens.At step S3605 a value of 300 is set in the AF pulse counter, and at stepS3607 the AF pulse counting process is called. In the AF pulse countingprocess the AF pulse counter is decremented based on the pulse signalsoutput to the CPU 210 from the AF reference pulse input circuit 222 insynchronization with the rotation of the rear lens group driving motor30.

The AF pulse counting process is ended when the pulses are not output tothe CPU 210 from the AF reference pulse input circuit 222 within apredetermined time, or when the count value of the decremented AF pulsecounter becomes 0.

After completion of the AF pulse counting process, at step S3609 therear lens group driving motor 30 is stopped. At step S3611, it is judgedwhether the AF pulse count remaining after being decremented in the AFpulse counting process is less than 100.

At step S3611, if the value of the AF pulse counter is less than 100,namely, if the value was decremented by 200 or more in the AF pulsecounting process, it is judged that the barrier was opened normally, andthe barrier opening process is ended. If the value of the AF pulsecounter is 100 or more at step S3611, it is considered that the rearlens group driving motor 30 cannot rotate due to some reason and theelimination of the obstruction is attempted by once rotating the rearlens group driving motor 30 clockwise, namely, in the direction in whichthe barrier closes, and then again counterclockwise. In such a manner,the obstacle can be removed.

At step S3613, the counter is decremented, and as long as the counterdoes not become 0 at step S3615, control proceeds to step S3619. At stepS3619, the rear lens group driving motor 30 is driven clockwise, a valueof 300 is set in the AF pulse counter, and the AF pulse counting processis called. After completion of the AF pulse counting process at stepS3623, the rear lens group driving motor 30 is stopped at step S3625,and control is returned to step S3603. Then the counterclockwise drivingof the rear lens group driving motor 30, the setting of the AF pulsecounter, the execution of the AF pulse counting process, and thestopping of the rear lens group driving motor 30 are made, and it isjudged whether the barrier is closed, according to the value of the AFpulse counter.

In the present embodiment, since the value of 3 is set in the counter atstep S3601, if the barrier is not opened at step S3611, the processesfrom steps S3613 to S3609 via S3625 are repeated twice. If the barrieropens in this process, the AF pulse counter will be less than 100 atstep S3611, and the barrier opening process is ended. If the value ofthe AF pulse counter does not become less than 100 after the last of therepetitions, it is judged that the barrier did not open and the barrieropening process is ended upon setting the error flag to 1 to indicatethe occurrence of a fault.

[The Zoom Driving Process]

FIG. 57 shows a flow chart for the zoom driving process. The zoomdriving process is a process to drive and control the whole unit drivingmotor 25 clockwise (i.e., in the direction in which the lenses areextended) by the amount corresponding to the value of the zoom pulsecounter, in order to cause the front lens group L1 and the rear lensgroup L2 to become focused at the subject distance, as shown in FIG. 34.

In the zoom driving process, at step S3701 the value of the zoom pulsecounter is stored in memory as a number of zoom pulses. Then at stepsS3703, S3705, S3707 and S3709, the zoom sequence is then set to 0 andthe whole unit driving motor 25 is driven clockwise, namely, in theadvancing direction, the zoom drive check process is executed, and theprocess waits until the zoom sequence becomes 5, after which control isreturned.

The zoom sequence is an identifier for identifying the operationsequence condition of the whole unit driving motor controlling circuit60. A zoom sequence of 0 indicates that the switching of the zoom codehas been detected, which serves as the reference point for the countingof the zoom pulses. A zoom sequence of 1 or 2 indicates the conditionwhere the zoom pulses are being counted, a zoom sequence of 3 indicatesthe activation of the reverse rotation brake, a zoom sequence of 4indicates the short-circuit braking condition, and a zoom sequence of 5indicates the open terminal condition (inactive condition) and thus theending of the series of the zoom drive sequences.

[The AF Two-stage Extension Process]

FIG. 58 shows a flow chart for the AF two-stage extension process. TheAF two-stage extension process is executed when the focal length of thelenses has been changed and is the process by which the rear lens groupL2 is extended by a predetermined amount (AP1) from the AF home positionwhen the lenses are positioned at the "wide" side.

When the AF two-stage extension process is called, at step S3801, theCPU 210 judges whether the rear lens group L2 is presently in thecondition where it has been extended by a predetermined amount by the AFtwo-stage extension process. In the latest execution of the AF two-stageextension process, if the lenses were positioned at the "wide" end side(i.e., the zoom step was less than 4), the rear lens group L2 would havebeen extended by a predetermined amount and the two-stage extension flagwould have been set to 1. If the zoom step was 4 or more when theprevious AF two-stage extension process was executed, the rear lensgroup would not have been extended (would be positioned at the AF homeposition) and the two-stage extension flag would have been set to 0.

When the AF two-stage extension process is called with the two-stageextension flag being set to 1 at step S3801, then at step S3805, the CPUjudges whether the zoom step corresponding to the present lens positionis greater than 4. If the zoom step is greater than 4, namely the rearand the front lens groups L1 and L2 are at the "tele" side, at stepsS3807 and S3809, the AF return process is called to return the alreadyextended rear lens group L2 to the AF home position, and control isreturned upon clearing the two-stage extension flag, i.e., setting theflag to 0. If the present zoom step is 4 or less, although the rear lensgroup L2 needs to be extended, since the rear lens group L2 has alreadybeen extended when the previous AF two-stage extension process wasexecuted, control is returned without executing any process.

If the two-stage extension flag is not 1 at step S3801, namely, if theflag is set to 0, this would mean that the rear lens group L2 waspositioned at the AF home position at the end of the previous AFtwo-stage extension process. In this case, at step S3803 the CPU 210judges whether the zoom step is 4 or less, and if the zoom step isgreater than 4 at step S3803, since it is not necessary to extend therear lens group L2 in other words, it is sufficient for the rear lensgroup L2 to remain at the AF home position, the extension of the rearlens group L2 is not executed, and control is returned. If the zoom stepis 4 or less, namely if the lenses are positioned at the "wide" side,the process of extending the rear lens group L2 is executed. However,process method will differ according to whether the lenses are at the"wide" end.

At step S3811, it is judged whether the value of the zoom step is 0, inother words, whether the lenses are positioned at the "wide" endposition. If the lenses are positioned at the "wide" end position, therear lens group driving motor 30 may be connected with the barrieropening device and is not connected to the rear lens group movingdevice. In other words, if the rear lens group driving motor 30 isdriven in the state where the lenses are positioned at the "wide" endposition, the rear lens group L2 may not be driven and theopening/closing of the barrier may be executed instead.

On the other hand, when the lenses are at the "tele" position, ratherthan at the "wide" position, the rear lens group driving motor 30 willalways be connected to the rear lens group moving device. Therefore,when the lenses are not positioned at the "wide" end, namely the zoomstep is not 0 at step S3811, the rear lens group L2 can be made toextend from the AF home position by an amount corresponding to the AFpulse number AP1 by setting the predetermined value AP1 at the AF pulsecounter (step S3823) and calling the AP drive process at step S3825.After extending the rear lens group L2 the CPU 210 sets the two-stageextension flag to 1, and control is returned.

When the value of the zoom step is 0, namely when the lenses arepositioned at the "wide" end at step S3811, as already described, apossibility exists that the rear lens group driving motor 30 may beconnected to the barrier opening device. However, as long as the AFtwo-stage extension process is called during the lens return process,the rear lens group driving motor 30 is guaranteed to be connected withthe rear lens group moving device. Therefore at step S3813, the processis branched according to the zoom return flag, which indicates whetherthe AF two-stage extension process being executed was called in the lensreturn process. If the present AF two-stage extension process was calledin the lens return process, the zoom return flag would be set to 1. Insuch a case, at step S3823 and step S3825, only the driving of the rearlens group L2 is executed.

On the other hand, it the present AF two-stage extension process wascalled from a process other than the lens return process, the zoomreturn flag would be set to 0, and the CPU 210 will therefore executethe processes from step S3815.

At steps S3815 and S3817, the CPU 210 sets the predetermined values ZP1and AP1 respectively in the zoom pulse counter and the AF pulse counter,and at step S3819 the lens driving process is called, and the front andrear lens groups L1 and L2 are firstly moved by an amount correspondingto the zoom pulse ZP1, by driving the whole unit driving motor 30, andsimultaneously the rear lens L2 is moved by an amount corresponding tothe AF pulse AP1, by driving the rear lens group driving motor 30. Afterthat, in the zoom return process at step S3821, the front and the rearlens groups L1 and L2 are returned by an amount corresponding to thevalue ZP1, by driving the whole unit driving motor 25. That is, thelenses are once moved to the "tele" position by the predetermined amountso that the rear lens group driving motor 30 is surely engaged with thedriving device of the rear lens group L2 and the rear lens group L2 isextended by driving the rear lens group driving motor 30. After, byreturning the front and rear lenses toward the "wide" position by thepredetermined amount, eventually the rear lens group L2 is only movedtoward the "wide" position.

As described above, at the point at which the AF two-stage extensionprocess is ended, if the lenses are at the "wide" position (i.e., thezoom step is not more than 4), the rear lens group L2 would be extendedby a predetermined amount and the two-stage extension flag would be setto 1. If the lenses are at the "tele" position (i.e., the zoom step isgreater than 4), the rear lens group L2 would be positioned at the AFhome position, and the two-stage extension flag would be set 0.

[The Zoom Return Process]

FIG. 59 shows a flow chart for the zoom return process. The zoom returnprocess is the process in which the front lens group L1 and the rearlens group L2 are returned to the standby position at which they werepositioned prior to being moved in the lens driving process during thephotographing process. In other words, in this process the whole unitdriving motor 25 is driven counterclockwise by an amount correspondingto the second zoom pulse ZP2 from the switching point at the housed sideof the present zoom code, in order to return the front lens group L1 andthe rear lens group L2 to the standby position, and is then stopped uponbeing rotated clockwise by an amount corresponding to the third zoompulse ZP3, to eliminate backlash to some degree, as shown in FIG. 34,i.e., the lens driving.

In the zoom return process at steps S3901, S3905, S3907, S3909 andS3911, it is checked whether the pulse number stored in the zoom pulsememory is less than the first zoom pulse value ZP1, and if it is less,the whole unit driving motor 25 is driven clockwise, namely driven formovement in the tele direction. Then the value of the pulse, obtained bydeducting the drive pulse value stored in the zoom pulse memory from thefirst zoom pulse value ZP1, is set in the zoom pulse counter, and thezoom pulse counting process is executed to wait until the value of thezoom pulse counter becomes 0. When the value becomes 0, namely when thewhole unit driving motor has been driven by an amount corresponding tothe value of the first zoom pulse ZP1 from the switching point of thepresent zoom code, the whole unit driving motor 25 is stopped. In such aprocess, when the lenses are stopped around the "tele" positionswitching point of the present zoom code, the zoom code may becomeunstable during the initial stages of passing current to the whole unitdriving motor 25, and the standby position may shift. For the purpose ofavoiding such an occurrence, the whole unit driving motor is drivenclockwise by an amount corresponding to the value of the first zoompulse ZP1 so that the zoom code will definitely turn OFF. Then at stepS3913, if the error flag is set to 1 control is returned, and if theerror flag is not set to 1 control proceeds to step S3915.

If the drive pulse number stored in the zoom pulse memory equals thefirst zoom pulse number ZP1 (indicating that the lenses have alreadybeen moved to the position at which the present zoom code turns OFF),the process of driving the whole unit driving motor 25 is skipped.

At step S3915, the whole unit driving motor 25 is drivencounterclockwise, namely, driven for movement in the "wide" direction.Then at steps S3917, S3919, S3923 and S3929, the zoom code input processis called to detect the zoom code, and it is checked whether the "wide"code is detected, whether the housing code is detected, and whether thepresent zoom code is detected. If the "wide" code was detected, the lens"wide" position is set, while if the housed condition is detected, thewhole unit driving motor 25 is stopped and control is returned afterexecuting the lens extension process (steps S3919, S3921 and S3923, orat steps S3923, S3925 and S3927).

If the present zoom code is detected at step S3929, then at step S3931the zoom code input process is executed. The process then waits untilthe OFF code is detected, namely, until the present zoom code turns OFF(step S3933). When the OFF code is detected, the second zoom pulse valueZP2 is set at the zoom pulse counter and the zoom pulse counting processis called to perform a waiting operation until the value at the zoompulse counter becomes 0 (steps S3935, S3937).

At step S3939, upon returning from the zoom pulse counting process, thewhole unit driving motor 25 is stopped. At steps S3941, S3943, S3945 andS3947, if the error flag was set to 1 namely, if the return wasperformed without the value at the zoom pulse counter becoming 0,control is returned without executing any process. While if the errorflag was not set, the whole unit driving motor 25 is driven in aclockwise direction, the backlash elimination pulse number ZP3 is set atthe zoom pulse counter, and the zoom pulse counting process is called towait for the value at the zoom pulse counter to become 0. Then at stepS3949, upon returning from the zoom pulse counting process, the wholeunit driving motor 25 is stopped and control is returned.

Thus by the zoom return process, the front lens group L1 is movedrearwardly to the standby position, which is retracted by the value ofthe second zoom pulse ZP2 from the rear end edge of the present zoomcode. At the standby position, backlash during a rotation of the wholeunit driving motor 25 in the "tele" direction is substantially removed.

[The Zoom Standby Confirmation Process]

FIG. 60 shows a flow chart for the zoom standby confirmation process.The zoom standby confirmation process is the process called during thephotographing process, in which, when the photometering switch SWS isON, it is confirmed whether the lenses are positioned at the correctstandby position, and if the lenses are not at the correct standbyposition, the lenses are moved to the correct standby position. Theprocesses after step S3931 of the zoom standby confirmation process, arethe same as those of the zoom return process.

In the zoom standby confirmation process, at steps S4001 and S4003, thezoom code input process is called and the zoom code is input, and if thepresent zoom code is not detected, control is returned since it isassumed that the lenses are at the correct standby position. If thepresent zoom code is detected at step S4003 (i.e., the lenses have movedfrom the standby position), at step S4005, the whole unit driving motor25 is driven counterclockwise, namely driven in the direction formovement to the "wide" side, and control proceeds to step S3931, and thezoom code input process is executed.

The detection of the OFF code is then waited for and when the OFF codeis detected, the second zoom pulse number ZP2 is set in the zoom pulsecounter, and the zoom pulse counting process is called to wait for thevalue at the zoom pulse counter to become 0 (steps S3933, S3935 andS3937).

At step S3939, upon returning from the zoom pulse counting process, thewhole unit driving motor 25 is stopped. At steps S3941, S3943, S3945 andS3947, if the error flag was set to 1 namely if control was returnedwithout the value at the zoom pulse counter becoming 0, the control isreturned without executing any process. While if the error flag was notset, the whole unit driving motor 25 is driven in a clockwise direction,the backlash elimination pulse number ZP3 is set at the zoom pulsecounter, and the zoom pulse counting process is called to wait for thevalue at the zoom pulse counter to become 0. Then at step S3949, uponreturning from the zoom pulse counting process, the whole unit drivingmotor 25 is stopped and control is returned.

As above described, in the zoom standby confirmation process, the frontlens group L1 and the rear lens group L2 are moved to the standbyposition, which is retracted by a predetermined distance from theswitching position at the "wide" side of the present zoom code, when thepresent zoom code corresponding to the zoom step is detected.

[The Photographing Charging Process]

FIG. 61 shows a flow chart for the photographing charging process. Thephotographing charging process is the process executed when thephotometering switch SWS is ON, and is the charging process called whenit is judged in the photographing process that strobe flashing isnecessary.

When the photographing charging process is called, at step S4101 the CPU210 judges whether the charge disable timer is set to 0. The chargedisable timer sets the period during which charging is disabled and acharge time of three seconds is set at this timer when the flashcapacitor 530 of the strobe device 231 becomes fully charged in the maincharging process shown in FIG. 41. In such a manner, if the time of thecharge disable timer has not expired (i.e., the timer value is not 0),although the charging of the flash capacitor 530 will be disabled,strobe flashing will be enabled since the capacitor 530 is almost fullycharged. Therefore if the time has not expired at the charge disabletimer at step S4101, then at step S4103 the charge-OK flag is set to 1to indicate that the strobe can be flashed, and at step S4104 thecharging demand flag is set to 0, and control is returned upon endingthe photographing charging process.

The time will not be up at the charge disable timer at step S4101, ifthe strobe device 231 is not fully charged or if three or more secondshave passed since the strobe device 231 was fully charged. In suchcases, since charging is not disabled, and the CPU 210 sets thecharge-OK flag to 0 at step S4102, and the processes for charging afterstep S4105 are executed.

At step S4105, the CPU 210 judges whether the charge interruption flagis set to 1. When a switch operation is performed while the maincharging process is being executed, the charging process is interruptedand the process corresponding to the operated switch is executed, and inthis process the charge interruption flag is set to 1.

If the charge interruption flag is set to 0, that is if the maincharging process was not interrupted at step S4105, a predeterminedlimit time (8 seconds) is set at the charging timer in order to restrictthe charging time. If the charge interruption flag is set to 1 at stepS4105, since the charging will be resumed, the charge interruption flagis cleared (set to 0) and the amount of the charge limiting timeremaining at the point at which charging was interrupted is set at thecharging timer (steps S4107 and S4109). In such a manner, even ifcharging is interrupted, a part of the predetermined charging limit time(8 seconds) will already have been spent in charging in the chargingprocess prior to the interruption. Since the charging time for thecharging process after interruption is set to the part of thepredetermined charging limit time (8 seconds) remaining after the abovementioned spent time, charging will have been performed for thepredetermined charging time when the charging is ended with the timebecoming up at the timer.

After the charging timer is set at step S4111 or S4109, the CPU 210 setsthe red lamp blinking flag to 1 and the red lamp 227 is blinked.Although the charging of the strobe flash capacitor 530 is executed inthe main charging process, without being recognized thereof by thephotographer, since the charging in the photographing charging processis executed while the photographer is pressing the shutter button 217halfway down, it is preferred to notify the photographer that chargingis in progress. For this purpose, in the photographing charging process,the red lamp 227 is blinked so that the photographer may recognize thatcharging is in progress.

When the charging timer is set, at step S4115 the charging signal is setto ON, namely the level at the terminal CHEN of the strobe device 231 isset to be H, and charging is started. The output of the terminal RLS ofthe strobe device 231, which corresponds to the charging voltage, isinput to the CPU 210 upon undergoing the A/D conversion. At step S4117the CPU 210 checks the A/D converted charging voltage. If the chargingvoltage has reached the level enabling strobe flashing at step S4119,then at step S4121 the CPU 210 sets the charge-OK flag to 1 to indicatethat strobe flashing is enabled, and at step S4123 the charging isstopped by setting the level at the terminal CHEN of the strobe circuit500 to low (L), and at step S4125 the red lamp blinking flag is set to0, and the blinking of the red lamp is stopped. In such a manner, thephotographer may recognize that the charging process is complete, namelythat the condition is no longer that in which the strobe cannot beflashed, in other words, photographing is now possible.

At step S4119, if the CPU 210 judges that the charging voltage has notreached the value enabling strobe flashing, then at step S4127 it isjudged whether the time at the charging timer has expired. If the timeat the charging timer expires, then at step S4123 the level at theterminal CHEN of the strobe circuit 500 is set to low (L) to stopcharging, and at step S4125 the red lamp blinking flag is set to 0 toend the blinking of the red lamp. If the time expires at step S4127, thecharge-OK flag will not be set to 1, since the charging voltage will nothave reached the level at which flashing is enabled.

If the time of the charging timer has not expired at step S4127, then atstep S4129 the CPU 210 judges whether the photometering switch SWS isOFF. If the photometering switch SWS is ON, the processes from stepsS4117 through S4127 are repeated. In such a manner, as long as theshutter button 217 is at least pressed halfway, charging is executeduntil the charging voltage reaches the level enabling flashing or untilthe charging time (eight seconds) has elapsed.

At step S4129, if the photometering switch SWS is judged to be OFF,namely if the half-pressed condition of the shutter button is canceledduring charging, then at step S4131 the CPU 210 makes the chargingsignal OFF, namely the CPU 210 turns OFF the charging signal, i.e., setsthe level at the terminal CHEN of the strobe circuit 500 to low, and atstep S4133 the remaining time, indicated by the charging timer, isstored in the memory, and at step S4135 the charge interruption flag isset to 1 to indicate that the charging has been interrupted. Then inorder to resume the execution of the remaining charging process canceledin the main charging process, at step S4137 the charging demand flag isset to 1, and then at step S4139 the red lamp blinking flag is set to 0to stop the blinking of the red lamp 227, and the photographing chargingprocess is ended. As above described, the remaining time stored in thememory at step S4133, and the charge interruption flag and the chargingdemand flag, are referenced during the execution of the main chargingprocess.

[The Focusing Process]

FIG. 62 shows a flow chart for the focusing process. In the focusingprocess, the whole unit driving motor 25 is driven clockwise (i.e., inthe direction in which the lenses are extended), and the rear lens groupdriving motor 30 is driven clockwise (i.e., in the retracting directionin which the rear lens group L2 is retracted) based on the whole unitdriving motor drive pulse number and the rear lens group driving motordrive pulse number calculated in the lens drive calculation process, tomove the front lens group L1 and the rear lens group L2 to the focusedposition, (see lens drive of FIG. 34). The present focusing process ischaracterized in that both the whole unit driving motor 25 and the rearlens group driving motor 30 are driven at the same time, i.e., driven inparallel.

In the focusing process, the zoom pulse counter value, namely, thenumber of pulses, calculated in the lens drive calculation process, bywhich the whole unit driving motor 25 is driven from the switching pointat the housed side of the present zoom code, is written into of the zoompulse memory at step S4201. The zoom sequence is then set to 0, and thewhole unit driving motor 25 is driven clockwise, and the driving checkprocess is executed to wait for the zoom sequence to become 1, namelyfor the present zoom code to be detected (i.e., turned from OFF to ON),and when the zoom sequence becomes 1, the AF sequence is set to 0 (stepsS4203, S4205, S4207, S4209 and S4211).

The rear lens group driving motor 30 is then driven clockwise, and it ischecked whether the value at the AF pulse counter is less than 50. Ifthe value is less than 50, the control of the rear lens group drivingmotor 30 is changed to low-speed control (i.e., pulse width modulation(PWM controlling), while if the value is not less than 50, controlproceeds to the zoom drive check process (steps S4213, S4215, S4217 andS4219, or at steps S4213, S4215 and S4219).

The process then waits for both the zoom sequence and the AF sequence tobecome 5, and when both become 5, namely when both the whole unitdriving motor 25 and the rear lens group driving motor 30 stop, controlis returned (steps S4219, S4221, S4223 and S4225).

In the focusing process, since both the whole unit driving motor 25 andthe rear lens group driving motor 30 are driven at the same time, thetime required for focusing by moving the front lens group L1 and therear lens group L2 to the focused position is shortened.

[The Exposure Process]

FIGS. 63 through 65 show a flow chart for the exposure process. Theexposure process is executed when the release switch SWR is turned ON.In the exposure process, the compensation process in regard to theshutter, and the shutter initial position confirmation process, etc.,are executed, and the shutter is thereafter released to performexposure.

Whether the AB adjustment has finished is checked at step S4301, and ifthe AE adjustment has not finished, or if the AE data is less than 10Eveven if the AE adjustment has finished, the AE timer time is selectedfrom among the fixed data stored in the ROM based on the AE dataobtained during the AE calculation process (steps S4301 and S4305, or atS4301, steps S4303 and S4305). If the AE adjustment has finished and theAE data is 10Ev or more, at steps S4301, S4303 and S4307, based on theAE data obtained during the AE calculation process, the AE timer time isdetermined from among the adjustment data read during the reset process.The fixed data in the ROM is used when the AE data is less than 10Evsince the shutter release time will be long when the AE data is lessthan 10Ev and the influence of errors will therefore be small, and sincethe process can be executed in a shorter time by using the data in theROM.

Then at steps S4309 and S4311, or at steps S4309 and S4313, whether theFM adjustment has completed or not is checked. If the FM adjustment hasnot completed, the FM timer time is selected from among the fixed datain the ROM based on the FM data, while if the FM adjustment hascompleted, the data that was read in the adjustment data reading processduring the reset process is used.

When the setting of the timers is completed, at steps S4315, S4317,S4319 and S4321, the shutter initial position confirmation process isexecuted. In the process, namely at steps S4315, S4317, S4319 and S4321,the AE motor 29 is driven counterclockwise to drive the shutter blades27a in the shutting direction, the AE pulse counting limit timer isstarted, and the AE pulse counting process is executed to wait until thetimer time expires. When the shutter blades 27a are completely shut, andbecome immovable, the time expires since the AE motor 29 becomesincapable of rotating.

When the time expires, at steps S4323 and S4325, the AE motor 29 isdriven clockwise and the shutter is driven in the opening direction, andthe AE pulse counting limit timer time is started. Then at steps S4327,S4329 and S4331, the AE pulse counting process is executed and theprocess waits until the reference pulse number is counted up in the AEpulse counting process, while checking whether the AE pulse countinglimit timer time has expired.

At steps S4329, S4333 and S4335, if the AE pulse counting limit timerhas expired, it represents that the rotation of the AE motor 29 isimpeded due to some reason, the shutter error flag is set, the AE motor29 is freed, namely the passage of current is stopped, and control isreturned.

At the moment when the counting of the reference pulse is ended, sincethe shutter blades 27a start to be opened. The AE timer and the FM timerare started, and the end-of-flash flag is cleared (steps S4335, 4337,S4339 and S4341).

Although it is checked whether the end-of-flash flag is set, and whetherthe flash mode is set, in the case where the strobe is not to beflashed, since the end-of-flash flag will remain cleared and the flashmode will not be set, the process waits for the time to expire at the AEtimer (steps S4343, S4345 and S4347).

When the time of the AE timer expires and if the bulb mode is not set,the AB motor 29 is driven counterclockwise (i.e., in the direction inwhich the shutter is closed) to start the shutter blade shuttingoperation and the AE pulse counting limit timer time is started (stepsS4371 and S4373). Then while executing the AE pulse counting process,the process waits for the time to expire at the AB pulse counter,namely, that the shutter blades 27a are shut and the AE motor 29 isstopped. When the time expires, the AE motor is freed and control isreturned (steps S4375, S4377 and S4379). In the case of the bulb mode,the AE motor 29 is freed while the photometering switch SWS is ON, inorder to prevent the AE motor 29 from overloading, and the process waitsfor the photometering switch SWS to be turned. OFF (steps S4365, S4367and S4369).

If the strobe flashing mode is set, since this means that a flashingmode is set, control proceeds to step S4349, and it is checked whetherflashing is in progress, and since flashing will not be in progressinitially, the process waits for the time to expire at the FM timer(steps S4349, S4351, S4347, S4313 and S4345). Since the FM timer time isnormally shorter than the AE timer time, the time will normally be up atthe FM timer first. When FM timer expires, flashing is started and the 2ms timer is started (steps S4351, S4353 and S4355). The 2 ms timer is atimer for waiting for the complete ending of the flashing of the strobe,and this waiting time is not limited to 2 ms and may differ according tothe characteristics of the strobe.

When flashing is started, since flashing will be in progress, theprocess waits until the 2 ms timer expires (steps S4349, S4357, S4347,S4343 and S4345). When the time of the 2 ms timer expires, the flashingis stopped, the end-of-flash flag is set, and the charging demand flagis set (steps S4357, S4359, S4361 and S4363). Then at steps S4343 andS4347, since the end-of-flash flag has already been set the processwaits until the AE timer expires.

[The Lens Return Process]

FIG. 66 shows a flow chart for the lens return process. The lens returnprocess is a process in which the front lens group L1 and the rear lensgroup L2 which been moved to the focused positions during thephotographing process, are returned to the positions prior to thephotographing process. The front lens group L1 is returned to thestandby position, retracted in the direction of the housing position byan amount corresponding to the second zoom pulse ZP2 from the "wide"side switching point of the zoom code corresponding to the zoom stepwhich identifies the present focal length. The rear lens group L2 isreturned to the AF home position if the zoom step is 5 or greater, ormoved to a position extended (i.e., retracted) from the AF home positionby an amount corresponding to the value of the AF pulse AP1, when thezoom step is between 0 and 4.

In the lens return process, the AF return process is called, the rearlens group L2 is returned to the AF home position, and the lens returnflag is set. Then the AF two-stage extension process is called, and ifthe zoom code is 5 or greater, the rear lens group L2 is left as it is.If the zoom code is 4 or less, the rear lens group L2 is extended (i.e.,retracted) by an amount corresponding to the value of the AP pulse AP1,and then the zoom return flag is cleared, i.e., set to 0. Then the zoomreturn process is called, and the front lens group L1 is moved to thestandby position of the present zoom code, and control is returned(steps S4401, S4403, S4405, S4407 and S4409).

[The Lens Drive Calculation Process]

FIG. 67 shows a flow chart for the lens drive calculation process. Thelens drive calculation process is the process in which the pulsenumbers, by which the whole unit driving motor 25 and the rear lensgroup driving motor 30 are to be driven, are determined based on thesubject distance (or the photographing distance) obtained in thefocusing processing and the present zoom step, as the zoom pulse numberfrom the "wide" side switching point (i.e., the ON/OFF point)corresponding to the present zoom step and the AF pulse value. In thefocusing process in the present embodiment, the direction in which thewhole unit driving motor 25 is driven is the direction in which thefront lens group L1 is advanced (extended), and the direction in whichthe rear lens group driving motor 30 is driven is the direction in whichthe rear lens group L2 is retracted from the AF home position, namely,moved away from the front lens group L1.

In the present embodiment, three modes of focusing are performed. At the"wide" end, whole focusing (first mode) is performed in which the frontlens group L1 and the rear lens group L2 are moved as a whole by thewhole unit driving motor 25. At the "tele" end, rear lens group focusing(third mode) is performed in which only the rear lens group L2 is movedby the rear lens group driving motor 30, and between the "wide" end andthe "tele" end, the front lens group focusing (second mode) is performedin which the front lens group L1 and the rear lens group L2 are moved bythe whole unit driving motor 25, and the rear lens group L2 is moved bythe rear lens group driving motor 30, so that the absolute position ofthe rear lens group L2 with respect to the camera will not be changed.

In the lens drive calculation process, at step S4501, the referenceamount of lens movement (i.e., the pulse number) Δ2T is calculated basedon the present zoom step and the subject distance obtained through thefocusing processing Then at steps S4503, S4505, S4507, S4509, S4511,S4513 and S4515, it is judged whether the present zoom step is 0 (i.e.,the "wide" end), between 1 and 12 (i.e., intermediate position betweenthe "wide" end and the "tele" end), or 13 (i.e., the "tele" end), andthe pulse calculation process corresponding to the zoom step is executedin accordance wit the present zoom step. At steps S4505 and S4507, ifthe present zoom step is at the "wide" end, the whole focusing will beperformed, and the value (a*Δ*2T) is set in the zoom pulse counter, andthe value 0 is set in the AF pulse counter. If the present zoom stepcorresponds to an intermediate position, the front lens group focusingwill be performed, and at steps S4509 and S4511, the value (b*Δ*2T) isset in the zoom pulse counter, and the value (c*Δ*2T) is set in the AFpulse counter. If the present zoom step corresponds to the "tele" end,the rear lens group focusing will be performed, and at steps S4513 andS4515, the value 0 is set in the zoom pulse counter, and the value(Δ*2T) is set in the AF pulse counter. The symbols a, b, c and ΔX arepredetermined compensation factors.

When the setting of the pulse counter is complete, at step S4517, thecorrection value X2f, according to the focal length, is added to thevalue of the AF pulse counter. Then at steps S4519 and S4521, theadjustment data is read from the EEPROM 230, and are further added tothe values at the AF pulse counter and the zoom pulse counter. At stepsS4523 and S4525 it is checked whether the AF two-stage extension flag isset, and if it is set, since the rear lens group L2 has already beenextended (retracted) by the value of the AF pulse AP1 from the AF homeposition, the value AP1 is deducted from the AF pulse counter.

In the above processing, the setting of the drive pulse number of thewhole unit driving motor 25 and the drive pulse number of the rear lensgroup driving motor 30, for moving the front lens group L1 and the rearlens group L2 to lens positions at which the lenses will be in focuswith the subject at the present focal length, are completed.

[The Test Function Process]

FIG. 68 shows a flow chart for the test function process. The testfunction process is the process for testing the functions of the camera,and is called to execute the various functions of the camera with thecamera being connected to a measuring device.

In the prior art, tests to be performed upon connecting a measuringdevice to a camera are commenced when commands are input into the camerafrom the measuring device, which are determined in advance andpredetermined processes are executed at the camera side according to thevarious commands input from the measuring device. However, when testsare performed by such a method, only a limited number of predeterminedoperations can be executed and other operations cannot be executed. Testoperations can only be performed for test items that are considered atthe time of writing the test program, and normally test items cannot beadded later. With the camera of the present embodiment, programs forcontrolling the camera can be designed one function at a time and inputfrom the measuring device to be executed by the camera.

The test function process is called during the execution of the resetprocess. Therefore, the test function process is executed by connectingthe measuring device (not shown) to the camera, as the battery is loadedinto the camera.

When the test function process is called, at step S7101 a handshakebetween the CPU 210 of the camera and the measuring device, connected tothe camera, is executed, and the communication condition is set. If anerror occurs during the handshake, or if the measuring apparatus is notconnected to the camera, it is deemed that the handshake wasunsuccessful at step S7103, and the test function process is canceled,and control is returned. If the handshake is successful andcommunication is enabled at step S7103, the input of commands from themeasuring device to the CPU 210 is enabled (step S7105).

If the command data has a value 0, which indicates the end of the testfunction process at step S7107, control is returned upon ending the testfunction process. If the value of the command data is not 0, the upperaddress and the lower address of the function to be called are receivedthrough serial communication from the measuring device (steps S7109,S7111) and the function stored in the address range is executed at stepS7113. The processes related to the test items necessary, are executedby repeating the above until the command data with a value of 0 isreceived.

As described above, detailed tests can be performed with the camera ofthe present embodiment, since the camera controlling programs can bedesigned and executed in function units by data input from the measuringdevice.

[The AF Pulse Counting Process]

FIG. 69 shows a flow chart for the AF pulse counting process. The AFpulse counting process is the process in which the AF pulse counter isdecremented by one each time a change in the AF pulse is detected withina predetermined time period, and the OK flag is set to 1 when the valueat the AF pulse counter becomes 0. The OK flag is set to 0 if the valueat the pulse counter does not become 0 within the predetermined period.

At step S7201, the CPU 210 first sets a timer to 200 ms, which isrepresentative of a period during which the changes in the AF pulses areto be monitored. In the following processes, if there is no change inthe AF pulse within 200 ms period, the CPU 210 sets the OK flag to 0, asabove described.

At step S7203, the CPU 210 judges whether the 200 ms timer has expired.If the time has not expired, then at step S7207, whether there was achange in the AF pulse is judged based on the output signal from the AFreference pulse input circuit 222 to the CPU 210. The judgement as towhether there is a change in the AF pulse is made by detecting thechange of the pulse from both the H (high) level to the L (low) leveland vice versa.

If there is no change in the AF pulse at step S7207, the CPU 210 returnsthe process to step S7203. Therefore, if no changes in the AF pulse aredetected within the 200 ms time period, it is judged that the timeexpires at step S7203, and the process is ended upon setting the OK flagto 0 at step S7205. In other words, the OK flag is set to 0 if the samenumber of pulses as the value set at the AP pulse counter before the AFpulse counting process was called is not detected during the executionof the AF pulse counting process.

When the CPU 210 detects a change in the AF pulse at step S7207, then atstep S7209 the timer is reset, and the period of 200 ms is set again andrestarted. If the detected change in the AF pulse is a rise of the AFpulse at step S7211, then at step S7213 the AF pulse counter isdecremented by one. Here, the value to be counted, that is, the valuecorresponding to the amount by which the rear lens group L2 is to bedriven by the rear lens group driving motor, is set at the AF pulsecounter before the AF pulse counting process is executed. If the valueat the decremented AF pulse counter is 0 at step S7215, the CPU 210 setsthe OK flag to 1 and ends the process. That is, the OK flag is set to 1if the same number of pulses as the value set at the AF pulse counterbefore the AF pulse counting process was called has been counted.

As described above, in the AF pulse counting process, the OK flag is setto 1 if the same number of pulses as the predetermined value set at theAF pulse counter are output from the AF reference pulse input circuit222 to the CPU 210. The OK flag is set to 0 if the output of pulses isstopped before the AF reference pulse input circuit 222 outputs a numberof pulses equal to the predetermined value set at the AF pulse counterto the CPU 210.

[The Zoom Drive Check Process]

FIG. 70 shows a flow chart for the zoom drive check process. Inaddition, the relationship between the driving state of the whole unitdriving motor 25 and the zoom sequence is shown in the form of a timingchart in FIG. 35. The zoom drive check process is a process in which itis judged at which stage the driving of the lenses by the whole unitdriving motor 25 for focusing on the subject distance is at, and inwhich stage the driving control of the whole unit driving motor 25 iscarried out.

When the zoom drive check process is executed, according to the value ofthe zoom sequence (0 through 5), which is the index that indicates thestate of driving of the whole unit driving motor 25, namely, the stateof operation of the whole unit driving motor controlling circuit 60, theprocess branches at step S7301. When the zoom drive check process iscalled, the condition will be one in which the whole unit driving motor25 is driven clockwise, and the zoom sequence is set to 0.

At step S7303, if the value of the zoom sequence is 0, the CPU 210 callsthe zoom code input process, and the value of the zoom code is input.When the lenses are stopped, the terminal for zoom code detection ispositioned to the "wide" side of the zoom code. When the whole unitdriving motor 25 is driven clockwise, the zoom code detection terminalfirst contacts the zoom code corresponding to the preset lens position.If the zoom code input in the zoom code input process equals to thevalue stored in the memory as the present zoom code at step S7305, thenat step S7307 the zoom sequence is set to 1. If the zoom code input bythe zoom code input process differs from the value stored in memory asthe present zoom code at step S7305, the zoom sequence remains at 0, andthe zoom drive check process is ended.

When the value of the zoom sequence is 1, namely, after the present zoomcode is detected, at step S7311 the CPU 210 monitors the rise of thezoom pulse output by the zoom pulse input circuit 220. At steps S7311and S7313, the zoom pulse is then only decremented if the rise of thezoom pulse is detected. When the zoom pulse counter becomes less than 20at step S7315, then at step S7317 the CPU 210 switches the whole unitdriving motor 25 to the low-speed control, and at step S7319, the valueof the zoom sequence is set at 2. If the value at the zoom pulse counteris equal to or greater than 20 at step S7315, the zoom sequence remainsat 1, and the zoom drive check process is ended.

Therefore, when the whole unit driving motor 25 is started to drive, thezoom pulse counter is decremented on the basis of the present zoom code,and according to the pulses output by the zoom pulse input circuit 220to the CPU 210. The whole unit driving motor 25 is driven by the normalDC drive until the count at the zoom pulse counter becomes 20. The zoomsequence will be 1 while the whole unit driving motor 25 is being drivenat normal speed. If the driving in the DC drive condition is continued,the lenses may be moved by more than the amount corresponding to thedesired number of pulses due to inertia, etc., when the whole unitdriving motor 25 stops. Therefore, when the zoom pulse counter becomesless than 20, the whole unit driving motor 25 is put under low speedcontrol. The low-speed control is executed by PWM control. When thedriving of the whole unit driving motor 25 is switched to low-speedcontrol, the zoom sequence is set to 2.

When the zoom sequence is 2, namely during the low-speed control of thewhole unit driving motor 25, if the zoom drive check process is called,the processes from step S7321 are executed. In such processes, at stepS7321 the CPU monitors a rise of the zoom pulse, and decrements the zoompulse when a rise is detected at step S7323. If a rise of the zoom pulseis not detected at step S7321, the process at step S7323 is skipped.

Until the zoom pulse count, which is decremented by one at a time whilethe lenses are being driven with the whole unit driving motor 25 beingunder low-speed control, become 0, the processes at steps S7321 andS7323 are executed each time the zoom drive check process is called. Thezoom sequence will remain at 2 during this period. When the zoom pulsebecomes 0 at step S7325, the whole unit driving motor 25 is drivencounterclockwise at step S7327, to perform the braking process (i.e.,reverse brake). After starting the counterclockwise driving of the wholeunit driving motor 25, at step S7328, the time of 5 ms, which is thereverse driving period, is set at the timer, and the zoom sequence isset to 3 at step S7329. In such a manner, when the zoom sequence is 3,the whole unit driving motor 25 is driven counterclockwise for braking.

When the zoom sequence is 3, if the zoom drive check process is called,at step S7331 the CPU 210 judges whether the period of 5 ms, which isthe period of the counterclockwise driving of the whole unit drivingmotor 25, has elapsed or not. If 5 ms has not elapsed, control isreturned with the zoom sequence remaining at 3. After 5 ms have elapsed,at steps S7333, S7335 and S7337, braking is performed byshort-circuiting the terminals of the whole unit driving motor 25, andthe 20 ms timer is started, and the zoom sequence is set to 4, andcontrol is returned.

If the zoom driving check processing is called when the zoom sequence is4, at step S7341 the CPU 210 monitors whether the zoom pulse changes.That is, whether the whole unit driving motor 25 is rotating under thecondition where the brakes are acting is judged according to whether thezoom pulse changes within 20 ms.

If the CPU 210 judges, that there is no change in the zoom pulse at stepS7341, and that the 20 ms timer expires at step S7345, then at stepsS7347 and S7349, the control of the whole unit driving motor 25 isstopped, and the terminals of the motor are brought in to the opencondition (i.e., undriven condition), and the zoom sequence is set to 5.If it is detected at step S7341 that the zoom pulse has changed, the 20ms timer is restarted at step S7343, and it is monitored whether thenext change in the zoom pulse is detected within the 20 ms after theprevious change in the zoom pulse. A return is performed with the brakeacting on the whole unit driving motor 25 and with the zoom sequenceremaining at 4 until it is judged at step S7345 that the 20 ms timer hasexpired.

If the zoom drive check process is called when the zoom sequence is 5,as shown in the flow chart, control is returned without executing anyprocesses in the zoom drive check process.

As above described, in the zoom drive check process, the lenses aremoved to the position of the present zoom code, which is the referenceposition (zoom sequence=0). The lenses are then moved at the normalspeed while the counter at the zoom pulse counter is 20 or more (zoomsequence=1), and then moved at a low speed when the count at the zoompulse counter becomes less than 20 (zoom sequence=2). When the count atthe zoom pulse counter becomes 0, the whole unit driving motor 25 isdriven counterclockwise for 5 ms (zoom sequence=3), and thereafter,braking is performed by short-circuiting the terminals of the whole unitdriving motor 25 (zoom sequence=4). When the whole unit driving motor 25comes to a complete stop, control of the whole unit driving motor 25 isended (zoom sequence=5), and thereafter, the undriven condition ismaintained, until a new value is set at the zoom pulse counter and thezoom sequence is set to 0.

[The AF Drive Process]

FIG. 71 shows a flow chart for the AF drive process. The AF driveprocess is a process in which the rear lens group motor 30 is driven andcontrolled so as to move the rear lens group rearwardly, i.e., towardsthe film plane, in the lens retracting direction. By this process, therear lens group L2 is moved rearwardly in order to set the focus on thesubject distance.

At step S7401 the AF sequence is first set to 0. At steps,. S7403 andS7405 the rear lens group driving motor 30 is driven clockwise, namely,driven in the retracting direction, and it is checked whether the countat the AF pulse counter is less than 50. If the count is less than 50,the control of the rear lens group driving motor 30 is switched tolow-speed control (i.e., the PWM control), while if the count is 50 orgreater, the AF drive check process is called without switching thecontrol (steps S7405, S7407 and S7409, or at steps S7405 and S7409).Then at steps S7409 and S7411, it is then waited for the AF sequence tobecome 5 while performing the AF drive check process and a return isperformed when the sequence becomes 5.

The AF sequence is an identifier which identities the state of theoperation sequence of the rear lens group driving motor controllingcircuit 61, and as shown in FIG. 35 and FIG. 36, an AF sequence of 0indicates the condition where the switching of the AF home signal, basisfor the counting of AF pulses, has been detected. An AF sequence of 1and 2 indicate the condition in which the AF pulses are being countedwith 1 indicating the DC drive condition and 2 indicating the low-speedcontrol condition. An AF sequence of 3 indicates the reverse brakingcondition, 4 indicates the short-circuit braking condition, and 5indicates the open terminal condition (inactivated condition) and thusthe ending of the series of sequences.

If the rear lens group driving motor 30 is driven by the DC drive whenthe AF pulse number by which the rear group moving motor 30 is to bedriven is small, the rear lens group driving motor 30 may be driven, dueto inertia, etc., by more than the AF pulse number by which it issupposed to be driven. Thus when the AF pulse number is less than 50,the start-up and driving are performed from the beginning at the samelow speed as in AF sequence 2.

[The Zoom Pulse Counting Process]

FIG. 72 shows a flow chart for the zoom pulse counting process. The zoompulse counting process is a process in which the previously set zoompulse counter is decremented by one each time a change in the zoom pulseoutput from the zoom pulse input circuit 220, is detected within apredetermined period, and which is ended when the count at the zoompulse counter becomes 0. If a change in the zoom pulse is not detectedwithin the above mentioned predetermined period, the error flag is setto 1.

At step S7501, the CPU 210 first sets the period of 200 ms at the timeras the period during which the change in the zoom pulse is to bemonitored. In the following processes, if there is no change in the zoompulse within 200 ms, the CPU 210 sets the error flag to 1.

At step S7503, the CPU 210 judges whether the 200 ms timer has expired.If the time has not expired, then at step S7507, it is judged whetherthere was a change in the zoom pulse based on the output pulse from thezoom pulse input circuit 220 to the CPU 210. Whether the zoom pulsechanged is judged here by detecting the change in the pulse both fromthe H (high) level to the L (low) level and vice versa.

If there is no change in the zoom pulse at step S7507, the CPU 210returns to the process at step S5703. Therefore, if the change in thezoom pulse is not detected within 200 ms, at step S7503 it is judgedthat the time expires, and at step S7505 the error flag is set to 1 andcontrol is returned. In other words, a return is performed upon settingthe error flag to 1 if the same number of pulses as the value set at thezoom pulse counter before the zoom pulse counting process was called isnot detected within the interval during which the zoom pulse countingprocess is executed.

When the CPU 210 detects a change in the zoom pulse at step S7507, thenat step S7509 the timer is reset to 200 ms. If the detected change inthe zoom pulse is a rise of the zoom pulse at step S7511, then at stepS7513 the zoom pulse counter is decremented by one. Here, the value tobe counted, that is, the value corresponding to the amount by which thelenses are to be driven by the whole unit driving motor 25 (i.e., thecount of the pulses output by the zoom pulse input circuit 220), is setat the zoom pulse counter before the zoom pulse counting process isexecuted. When the count of the zoom pulse counter becomes 0 at stepS7515, the CPU 210 ends the process. That is, the process is endednormally if the same number of pulses as the value set at the zoom pulsecounter before the zoom pulse counting process was called has beencounted.

As described above, in the zoom pulse counting process, a return isperformed without setting the error flag if the same number of pulses asthe value set previously at the zoom pulse counter are counted. On theother hand, a return is performed upon setting the error flag to 1 ifthe same number of pulses as the value set at the zoom pulse counter bythe zoom pulse input circuit 220 could not be counted.

[The AF Drive Check Process]

FIG. 73 shows a flow chart for the AF drive check process. The AF drivecheck process is a process in which the rear lens group driving motor 30is controlled so that the rear lens group L2 will be driven based on thevalue set at the AF pulse counter.

The execution the AF drive check process which branch at step S7601 isprocessed in accordance with the value of the AF sequence (0 through 5).The AF sequence is an identifier that identifies the state of theoperation sequence of the rear lens group driving motor controllingcircuit 61. When the AF drive check process is executed for the firsttime, the rear lens group driving motor 30 is driven, and the AFsequence is set to 0. FIG. 35 shows the relationship between the drivingstate of the rear lens group driving motor 30 and the AF sequence.

At step S7603, if the value of the AF sequence is 0, the CPU 210 judgeswhether the AFH (i.e., the "AF home") signal has changed from H (high)to L (low). The AFH signal is H (high) when the rear lens group L2 ispositioned at the AF home position, and changes to L (low) when the rearlens group L2 moves away from the AF home position. The movement of therear lens group L2 based on the AF pulse counter, described below, isexecuted on the basis of the position at which the AFH signal changes toL. When the AFH signal changes from H to L at step S7603, then at stepS7605 the CPU 210 sets the AF sequence to 1, and control is returned.While the AFH signal is H, control is returned while the AF sequenceremains at 0.

If the value of the AF sequence is 1, namely, after the change of theAFH signal from H to L is detected, at step S7611 the CPU 210 monitorsthe rise of the AF pulse. At steps S7611 and S7613, the AF pulse counteris decremented only when the rise of the AF pulse is detected. When thecount at the AF pulse counter becomes less than 200 at step S7615, thenat step S7617 the CPU 210 switches the rear lens group driving motor 30to low-speed control, and at step S7619, the value of the AF sequence isset to 2. If the AF pulse counter is 200 or more at step S7615, the AFdrive check process is ended and control is performed with the AFsequence remaining at 1. If the DC drive of the rear lens group drivingmotor 30 is performed from the beginning to the end, the desired AFpulse number may be exceeded due to the influence of inertia, etc. Thus,when the remaining AF pulse number becomes 200, the rear lens groupdriving motor 30 is driven at low speed through the PWM control.

As described above, when the rear lens group driving motor 30 is startedto drive, the AF pulse counter is decremented based on the point atwhich the AFH signal changes from H to L, and normal DC drive of therear lens group driving motor 30 is performed until the count at the AFpulse counter becomes 200. While the normal drive of the rear lens groupdriving motor 30 is being performed, the AF sequence will be 1. When thecount at the AF pulse counter becomes less than 200, the rear lens groupdriving motor 30 is driven under low-speed control. When the rear lensgroup driving motor 30 comes under low-speed control, the AF sequence isset to 2.

When the AF drive check process is called when the AF sequence is 2,that is, when the rear lens group driving motor 30 is under low-speedcontrol, the processes from step S7621 are executed. In such processes,at step S7621 the CPU 210 monitors the rise of the AF pulse, and if arise of the AF pulse is detected, at step S7623 the zoom pulse counteris decremented. If the rise of the AF pulse is not detected at stepS7621, the process at step S7623 is skipped.

The AF pulse count is decremented by one at a time while the rear lensgroup L2 is being driven with the rear lens group driving motor 30 beingunder low-speed control. Before the AF pulse count becomes 0, theprocesses at steps S7621 and S7623 are executed each time the AF drivecheck process is called. In such a case, the AF sequence will remain at2. When the AP pulse count becomes 0, by driving the whole rear lensgroup driving motor 30 counterclockwise at step S7627, the brakingprocessing (i.e., reverse brake) is executed. After starting thecounterclockwise driving of the rear lens group driving motor 30, atstep S7628, the time of 5 ms, which is the counterclockwise drivingperiod, is set at the timer, and the AF sequence is set to 3 at stepS7629. In such a manner, when the AF sequence is 3, the rear lens groupdriving motor 30 is driven counterclockwise for braking.

When the AF sequence is 3, if the AF driving check processing is called,at step S7631 the CPU 210 judges whether the period of 5 ms has elapsed,and if 5 ms has not elapsed control is returned with the AF sequenceremaining at 3. After 5 ms has elapsed, then at step S7633, step S7635and step S7637, the braking is activated by short-circuiting theterminals of the rear lens group driving motor 30, and the 20 ms timeris started, and the AF sequence is set to 4, and control is returned.

If the AF drive check process is called when the AF sequence is 4, atstep S7641 the CPU 210 monitors whether the AF pulse changes. That is,whether the rear lens group driving motor 30 is rotating under thecondition where the brake is acting, is judged according to whether theAF pulse changes within 20 ms.

If the CPU 210 judges, that there is no change in the AF pulse at stepS7641, and that the 20 ms timer has expired at step S7645, at stepsS7647 and S7649, the control of the rear lens group driving motor 30 isstopped, and the terminals of the motor are brought into the opencondition (i.e., undriven condition), and the AF sequence is set to 5.If the change of the AF pulse is detected at step S7641, the 20 ms timeris restarted at step S7643, and it is monitored whether the next changein the AF pulse is detected within 20 ms after the previous change inthe AF pulse. At step S7645, a return is performed with the brake actingon the rear lens group driving motor 30 and with the AF sequenceremaining at 4 until it is judged that the 20 ms timer has expired.

If the AF drive check process is called when the AF sequence is 5, asshown in the flow chart, the control is returned without executing anyprocesses in the AF drive check process.

As above described, in the AF drive check process, the lenses arefirstly moved to the reference position at which the AFH signal becomesL (the AF sequence=0). The rear lens group is then moved by the normalDC drive while the count at the AF pulse counter is 200 or more (the AFsequence=1), and then moved at low speed by PWM when the count at the AFpulse counter becomes less than 200 (the AF sequence=2). When the countat the AF pulse counter becomes 0, the rear lens group driving motor 30is driven counterclockwise for 5 ms (the AF sequence=3), and thereafter,braking is performed by short-circuiting the terminals of the rear lensgroup driving motor 30 (the AF sequence=4). When the rear lens groupdriving motor 30 comes to a complete stop, its control is ended (the AFsequence=5), and thereafter, the rear lens group driving motor 30 is notcontrolled (undriven condition is entered), until a new value is set atthe AF pulse counter and the AF sequence is set to 0.

A detailed description of the barrier apparatus and the rear lens groupdriving device in the present embodiment will now be described withreference to FIGS. 74-93.

As shown in FIGS. 87 and 88, the lens barrier apparatus 35, equippedwith the pair of follower barrier blades 48a and the pair of mainbarrier blades 48b (four barrier blades in total), and is mounted at thefront of the first moving barrel 20 positioned at the front of the zoomlens barrel 10. The annular plate 96 is fixed on the periphery of thedecorative plate 41 which is fixed to the front end of the first movingbarrel 20. Both pairs of barrier blades 48a and 48b are pivotallyattached between the decorative plate 41 and the annular plate 96. Abarrier driving ring 97 provided with a pair of barrier driving levers98a and 98b is rotatably mounted between a front end surface 20c of thefirst moving barrel 20, i.e., in the space surrounded by the firstmoving barrel 20 and an inner periphery flange 20b formed on the frontpart of the first moving barrel 20, and the annular plate 96. Thebarrier driving ring 97 is rotated clockwise and counterclockwise via abarrier coupling gear shaft 92 which rotates upon receiving a rotationfrom the rear lens group driving motor 30. The barrier coupling gearshaft 92 has a driving gear 92a at its front end, and a driven gear 92bat its rear end. The rotation of the rear lens group driving motor 30 istransmitted to the driven gear 92b via a certain gear train. The barrierdriving ring 97 opens and closes the main barrier blades 48b togetherwith the follower barrier blades 48a via the barrier driving levers 98aand 98b which are attached pivotally to the barrier driving ring.

The mechanism of the barrier driving device in the present embodimentwill now be described with reference chiefly to FIGS. 87-93. Of the fourbarrier blades, only one main barrier blade 48b is shown by the chaindouble-dashed line in the drawings in FIGS. 89-92, for the purpose ofillustration.

As shown in FIG. 88, a supporting insertion hole 20d is formed on theinner periphery flange 20b of the first moving barrel 20, at a positionopposite to a hollow 111 (see FIG. 8) formed on the presser 53 of theAF/AE shutter unit 21. The barrier coupling gear shaft 92 has a drivinggear 92a extending by a predetermined amount from the supportinginsertion hole 20d in the condition where the driven gear 92b isinserted through the hollow 111 to engage with a final gear 42b of thebarrier opening gear train 42c (i.e., the second gear train), as shownin FIGS. 75 and 76. The driving gear 92a of the barrier coupling gearshaft 92 engages with a sector gear 97a formed on the rear surface ofthe barrier driving ring 97, as shown in FIG. 87. With the abovestructure, when the barrier coupling gear shaft 92 rotates clockwise orcounterclockwise upon receiving the rotation of the rear lens groupdriving motor 30, the barrier driving ring 97 is respectively rotatedclockwise or counterclockwise about the optical axis O.

As shown in FIGS. 87-89, the barrier driving ring 97 is formed in such amanner that the diameter of the outer peripheral rim thereof is slightlysmaller than that of the inner peripheral face of the barrel 20c, andthat the diameter of the inner peripheral rim thereof is slightly largerthan that of the outer periphery of a cylinder part 34a.

On the rear surface of the decorative plate 41, a pair of pivots (nowshown) are fixed, with one pivot being positioned substantially oppositethe other with respect to the optical axis O. These pivots are rotatablyfitted to hollows 102, formed respectively on each of the pair of mainbarrier blades 48b, and to hollows 103, formed respectively on each ofthe pair of follower barrier blades 48a. Each main driven barrier blade48b opens and closes the photographing aperture by rotating with thecorresponding follower barrier blade 48a about the corresponding pivot.Each of the pair of main barrier blades 48b is provided with a boss 101at a position eccentric with respect to its hollow 102. Each boss 101 isinserted through a corresponding opening 96a on the annular plate 96.Each of the pair of follower barrier blades 48a is provided with anengaging projection 100 projecting rearwards in the optical axis Odirection, which engage with outer rims (edges) of the correspondingmain barrier blade 48b, located on the inner side thereof, in order tofollow the opening-closing operation of the main barrier blade 48b.

On the front wall of the barrier driving ring 97, shafts 97h and 97i arefixed with one shaft part being positioned substantially opposite theother one with respect to the optical axis O. Each of the barrierdriving levers 98a and 98b is provided with a cam groove 107 (as shownin FIG. 89) into which the boss 101 of the corresponding main barrierblade 48b is fitted. On each barrier driving lever 98a and 98b, shaftgrooves 120 are formed at intermediate positions along the length of thecam grooves 107. Also, each of the shafts 97h and 97i is, rotatablyfitted about the corresponding shaft groove 120. Each of the shaftgrooves 120 is disposed near the corresponding hollow 102. The barrierdriving levers 98a and 98b are respectively provided with engaging parts109 at one end and engaging parts 110 at the other end.

A coil 105c of a torsion spring 105 is engaged on the front wall of thebarrier driving ring 97 at a protrusion 97e provided at a position toone side of the line connecting the pair of hollows 102 of the pair ofmain barrier blades 48b. The torsion spring 105 is engaged for thepurpose of urging the pair of barrier driving levers 98a and 98b torotate in a clockwise direction. As such, one end 105a thereof isconnected with the engaging part 109 at one end of the barrier drivinglever 98a. Further, between the torsion spring 105 and one of thebarrier driving levers 98b, a reverse lever 104 is positioned to reversethe direction of the force of the torsion spring 105. On the front wallof the barrier driving ring 97, a shaft 97j is fixed between the barrierdriving lever 98b and the protrusion 97e, and the reverse lever 104 isrotatably fitted on the shaft 97j. The reverse lever 104 has an engagingpart 104b at one end, which is engaged with another end 105b of thetorsion spring 105, and another engaging part 104a at the other end,which is engaged with the other end engaging part 110 of the barrierdriving lever 98b.

Restricting protrusions 97f and 97g, extending radially outward atpredetermined positions, are disposed at both sides of the protrusion97e of the barrier driving ring 97 in order to restrict the deformationof the end parts 105a and 105b of the torsion spring 105.

The cam grooves 107, provided respectively at the barrier driving levers98a and 98b, are respectively equipped with a first opening section 107aand a second opening section 107b. Although the first and second openingsections 107a and 107b are somewhat stepped at their middle boundaryparts, they are generally arranged to be substantially straight.

During the barrier opening operation when the barrier driving ring 97rotates from the position at which the barriers are fully closed (i.e.,the position shown in FIG. 89) to the intermediate open position (i.e.,the position shown in FIG. 90), the first opening section 107a serves asa forcible opening section and forcibly moves the pair of main barrierblades 48b to move in the opening direction. During the barrier closingoperation when the barrier driving ring 97 rotates from the intermediateopen position (i.e., the position shown in FIG. 90) to the position atwhich the barriers are fully closed (i.e., the position shown in FIG.89), the first opening section 107a serves as a spring urging sectionfor urging the pair of main barrier blades 48b in the closing directionby the torsion spring 105.

During the barrier closing operation when the barrier driving ring 97rotates from the position at which the barriers are fully opened (i.e.,the position shown in FIG. 91) to the intermediate open position (i.e.,the position shown in FIG. 90), the second opening section 107b servesas a forcible opening section and forcibly moves the pair of mainbarrier blades 48b in the closing direction. During the barrier openingoperation when the barrier driving ring 97 rotates from the intermediateopen position (i.e., the position shown in FIG. 90) to the position atwhich the barriers are fully opened (i.e., the position shown in FIG.91), the second opening section 107b serves as a spring urging sectionfor urging the pair of main barrier blades 48b in the opening directionby the torsion spring 105.

The barrier driving ring 97 also has the above mentioned sector gear97a, for rotatably driving the barrier driving ring 97 itself uponreceiving the rotation of the barrier coupling gear shaft 92, at theother side of the line joining the pair of hollows 102 of the pair ofmain barrier blades 48b. The sector gear 97a is formed on an innerperiphery of an arched groove 97d provided on the rear surface of thebarrier driving ring 97.

The lens barrier apparatus 35, having the above structure, is operatedas follows. When the barrier coupling gear shaft 92 rotates in onedirection (i.e., the clockwise direction in FIG. 89) in the fully closedposition, at which the zoom lens barrel 10 is at the lens housedposition, and the various members are positioned as shown in FIG. 89,the barrier driving ring 97 is rotated counterclockwise via the sectorgear 97a. During rotation of the barrier driving ring 97, the barrierdriving levers 98a and 98b respectively move the pair of main barrierblades 48b as follows.

In the state as shown in FIG. 89, when the barrier driving ring 97rotates counterclockwise from the barrier-closed position towards theintermediate open position, each of the barrier driving levers 98a and98b firstly moves the corresponding boss 101 towards the optical axis O,via the first opening sections 107a of the cam grooves 107, i.e., fromthe state shown in FIG. 89 to the state shown in FIG. 90. When thebarrier driving ring 97 is moved further in the same direction, each ofthe barrier driving levers 98a and 98b moves the corresponding boss 101further toward the optical axis O, via the second opening sections 107bof the cam grooves 107, i.e., from the state shown in FIG. 90 to thestate shown in FIG. 91. By this movement, both the pair of main barrierblades 48b and the pair of follower barrier blades 48a are brought tothe opened condition. When the barrier coupling gear shaft 92 rotates inthe opposite direction (i.e., counterclockwise shown in FIG. 91) fromthe state as shown in FIG. 91, the barrier driving ring 97 is rotated inthe clockwise direction via the sector gear 97a, namely in the clockwisedirection as shown in FIG. 91. Thereafter, the pair of main barrierblades 48b and the pair of follower barrier blades 48a are both broughtto the closed condition through an operation that is the reverse of thatof the above-described operation performed when the barrier driving ring97 is rotated in the counterclockwise direction of FIG. 89.

The mechanism by which the rotation of the rear lens group driving motor30 is transmitted to the lens barrier apparatus 35 via the barriercoupling gear shaft 92 will now be described in detail with reference toFIGS. 74-87.

As shown in FIG. 79, the shutter mounting plate 40 is provided with anannular part 40f which extends in the direction perpendicular to theoptical axis O, and the rear lens group driving motor 30 is fixed to thefront surface of the annular part 40f Provided on the front wall and therear wall of the annular part 40f are a lens driving gear train 42Awhich transmits the rotation of a pinion 30a fixed to the rotating shaftof the rear lens group driving motor 30, and an encoder gear train 42Bwhich transmits the rotation of the pinion 30a. The encoder gear train42B is the gear train used to transmit the rotation of the rear lensgroup driving motor 30 to a rotation shaft 58f (FIG. 75) of the rotatingplate 58, and the rotation of the rear lens group driving motor 30 isalways transmitted to the rotation shaft 59f via the encoder gear train42B. Further, a barrier opening gear train 42C is provided on theannular part 40f, in order to transmit the rotation of the lens drivinggear train 42A to the barrier coupling gear shaft 92, so that the lensbarrier of the lens barrier apparatus 35, namely the pair of mainbarrier blades 48b and the pair of follower barrier blades 48a, may beopened or closed.

In the lens gear train 42A, a planetary gear 93 (FIG. 74) consisting ofa planet gear 93a and a sun gear 92b is provided. When the zoom lensbarrel 10 moves from the lens extended position to the lens housedposition, the position of the planetary gear 93 is switched from theposition shown in FIG. 75 to the position shown in FIG. 76, via aswitching cam 122 (see FIGS. 80-82). The planet gear 93a is engaged withan input gear 42c of the barrier opening gear train 42C in the stateshown in FIG. 76, and the planet gear 93a is engaged with the drivinggear 42a with which the screw shaft 43 is engaged in the state shown inFIG. 75. The driving gear 42a is the final gear of the lens driving geartrain 42A. When the rear lens group driving motor 30 drives forward(clockwise) and in reverse (counterclockwise) in the state shown in FIG.75, the barrier driving ring 97 is driven clockwise and counterclockwisevia the barrier coupling gear shaft 92, and the lens barrier of the lensbarrier apparatus 35 is opened and closed. In addition, when the rearlens group driving motor 30 drives forward (clockwise) and in reverse(counterclockwise) in the state shown in FIG. 75, the driving gear 42ais driven clockwise and counterclockwise, and the rear lens group L2 ismoved relative to the front lens group L1 via the screw shaft 43.

The planet gear 93a and the sun gear 93b of the planetary gear 93 aresupported by a rotation switching member 130 as shown in enlarged formin FIGS. 79-82. The rotation switching member 130 is provided with abase 130a parallel to the annular part 40f. On the rear surface of thebase 130a, a primary shaft 130b is fixed at one end, and a secondaryshaft 130c is fixed at the other end. On the front surface of the base130a, a shaft 130f coaxial with the primary shaft 130b is fixed at oneend, and a driven shaft 130d. approximately coaxial with the secondaryshaft 130c is fixed at the other end. The primary shaft 130b, thesecondary shaft 130c, the driven shaft 130d and the shaft 130f are allparallel to the optical axis O.

The sun gear 93b is rotatably fitted to the primary shaft 130b, and theplanet gear 93a is rotatably fitted to the secondary shaft 130c. The sungear 93b is fitted into a depressed bearing surface 40h formed on thefront face of the annular part 40f and in this condition, a front endpart 130e of the primary shaft 130b is inserted in and rotatablysupported by a hole 40i formed in the center of the depressed bearingsurface 40h. The shaft 130f is rotatably fitted into a guide hollow (notshown) formed at a position corresponding to the presser 53. It can beunderstood that with the above structure, when the rotation switchingmember 130 rotates about the primary shaft 130b, the planet gear 93aswitches between the position shown in FIG. 75 and the position shown inFIG. 76.

The driven shaft 130d of the rotation switching member 130 passesthrough and protrudes towards the front from a guide slot 53j, formed onthe presser 53, and is inserted into a hollow 122a of the switching cam122, supported rotatably by the presser 53.

The switching cam 122 is provided with a shaft insertion hole 122b atthe center thereof, and the presser 53 is provided with a shaft 53iwhich is rotatably fitted into the shaft insertion hole 122b. The shaft53i is longer than the shaft insertion hole 122b by a predeterminedamount and a front end thereof is fitted into the hole 55a of thepresser plate 55, fixed to the front of the presser 53. Around the shaftinsertion hole 122b, the switching cam 122 is provided with a hole 122a,an engaging pin 122c which extends forward in the optical axisdirection, and an engaging cam 122d. On the inner periphery of the frontend of the engaging cam 122d, a cam surface 123 is formed. The camsurface 123 is formed as a surface that gradually inclines toward therear lens group driving motor 30 from a rear end 123a to a front end123b thereof. When the relative position between the AF/AE shutter unit21 and the linear guide member 22 becomes a predetermined position, thecam surface 123 engages with the engaging part 22f at the front end ofone of the guide legs 22b provided on the linear guide member 22.Therefore, the relative position, in the optical axis direction, betweenthe cam surface 123 of the switching cam 122 and the engaging part 22fof the linear guide member 22, is strictly set.

Between the shaft insertion hole 122b of the switching cam 122 and thepresser 55, a coil spring 124, fitted to the shaft 53i, is provided. Theswitching cam 122 is constantly urged rearwards in the optical axisdirection by the coil spring 124. Further, a torsion spring 125 isfitted to a fixing post 53k, fixed on the presser 53 and engages with ascrew 127, to fix one end of the presser 55. One end 125a of the torsionspring 125 engages with a fixing part 53m of the presser 53, and anotherend 125b engages with the engaging pin 122c of the switching cam 122.The switching cam 122 is constantly urged by the torsion spring 125 inthe counterclockwise direction with respect to the view of the AF/AEshutter unit 21 from the subject side. In addition, since the drivenshaft 130d of the rotation switching member 130 is inserted through theguide slot 53j, the rotation switching member 130 is also urged in thesame direction by the torsion spring 125. When the AF/AE shutter unit 21and the linear guide member 22 are in a mutually separated condition,the switching cam 122 is fitted to the shaft 53i in such a state, asshown in FIG. 77, that an engaging part 122f formed close to theengaging pin 122c is contacted with an engaging projection 53n fixed tothe presser 53. Thus, in this condition, the switching cam 122 does notrotate in the clockwise direction with respect to the view of the AF/AEshutter unit 21 from the subject side. At this time, the relativepositional relationship between the switching cal 122 and the rotationswitching member 130 will be as shown in FIG. 80. From such a state, ifthe engagement of the engaging projection 53n with the engaging part122f is released by moving the switching cam 122 forwardly (i.e., in thedirection indicated by an arrow in FIG. 80) against the urging force ofthe coil spring 124, it is possible to rotate clockwise.

When the power supply of the camera is turned OFF, and the linear guidemember 22 is in the condition shown in FIG. 83 (photographingcondition), the transition to the condition shown in FIG. 84, namely tothe housed condition, is carried out. In this process, the engaging part22f of the linear guide member 22 contacts the front end 123b of the camsurface 123, and then when the linear guide member 22 and the AF/AEshutter unit 21 move closer, since the engaging part 22f presses the camsurface 123 forwardly in the optical axis direction, the switching cam122 is moved forwardly, and the engagement of the engaging projection53n and the engaging part 122f becomes disengaged. At this time, theswitching cam 122 and the rotation switching member 130 will be in therelative positional relationship as shown in FIG. 81.

Thereafter, when the linear guide member 22 and the AF/AE shutter unit21 move much closer, the switching cam 122 rotates in the clockwisedirection (i.e., in the direction shown by the arrow in FIG. 81) withrespect to the view of the AF/AE shutter unit 21 from the subject side,while sliding the cam surface 123 against the engaging part 22f of thelinear guide member 22. During this rotation, the rotation switchingmember 130 is also rotated in the same direction via the hole 122a andthe driven shaft 130d, and by such a rotation, the engagement of theplanet gear 93a with the driving gear 42a is disengaged.

Thereafter, as shown in FIG. 84, when the linear guide member 22 and theAF/AE shutter unit 21 become closest to each other, the engaging cam122d rides the rims 22g of the guide legs 22b adjacent the engaging part22f. At this time, the switching cam 122 will be positioned at aposition rotated furthest in the clockwise direction with respect to theview of the AF/AE shutter unit 21 from the subject side, andsimultaneously, the rotation switching member 130 is also rotated in thesame direction, and is positioned at a position rotated furthest in theclockwise direction with respect to the view of the AF/AE shutter unit21 from the subject side. In this condition, the planet gear 93a engageswith the input gear 42c of the barrier opening gear train 42C. Whenthis. engagement is set, the rear lens group driving motor controllingcircuit 61 rotates the pinion 30a of the rear lens group driving motor30 in a predetermined direction, and this rotation is transmitted to thelens barrier apparatus 35 via the lens driving gear train 42A, thebarrier opening gear train 42C, and the barrier coupling gear shaft 92,and the lens barrier is eventually closed. From the housed state, whenthe power supply of the camera is turned ON, the rear lens group drivingmotor controlling circuit 61 firstly rotates the pinion 30a of the rearlens group driving motor 30 in the direction opposite theabove-mentioned predetermined direction to open the lens barrier of thelens barrier apparatus 35, and then extend the zoom lens barrel. By thisextension, the linear guide member 22 and the AF/AE shutter unit 21separate away from each other, and therefore the engagement between theguide legs 22b of the linear guide member 22 and the switching cam 122is disengaged, and the photographing condition shown in FIG. 83 is set.In such a photographing condition, the planet gear 93a is in a state ofengagement with the driving gear 42a.

As above described, in the zoo lens barrel 10 in the present embodiment,since the rotation of the rear lens group driving motor 30 istransmitted to the lens barrier apparatus 35 via the specified geartrains, the lens barrier is surely opened and closed.

As it understood from the above description, the present embodiment isprovided with at least a front lens group L1 and a rear lens group L2 aswell as a whole unit driving motor 25 for moving the front lens group L1and the rear lens group L2 as a whole, and a rear lens group drivingmotor 30 for moving the rear lens group L2 with respect to the frontlens group L1. When the front lens group L1 and the rear lens group L2are at a position that is retracted towards the camera body from apredetermined position, the front lens group L1 and the rear lens groupL2 are moved forwardly by driving the whole unit driving motor 25, andthen the rear lens group L2 is moved rearwardly by driving the rear lensgroup driving motor 30. Therefore, if any external force is applied tothe lens retraction direction to the front lens group L1 and the rearlens group L2 when retracted to the predetermined position, thepossibility that the rear lens group L2 collides with a film or anaperture frame 23 of the camera body is lessened, since the rear lensgroup L2 is moved rearwardly after extension of the front lens group L1and the rear lens group L2.

Further in the present embodiment, a lens barrier apparatus 35 isprovided which is driven to be opened and closed by the rear lens groupdriving motor 30. In addition, a switching mechanism is furtherprovided, by which, when the front lens group L1 and the rear lens groupL2 are at a housed position, the rear lens group driving motor 30 isconnected with the lens barrier apparatus 35, and when the front lensgroup L1 and the rear lens group L2 are extended from a predeterminedposition by the whole unit driving motor 25, the rear lens group drivingmotor 30 is connected with the rear lens group L2. When the front lensgroup L1 and the rear lens group L2 are at a predetermined position,after the front lens group L1 and the rear lens group L2 are extendedfrom the predetermined position by the whole unit driving motor 25, andthe rear lens group driving motor 30 is driven, therefore a switching ofconnection of the switching mechanism from the lens barrier apparatus 35to the rear lens group L2 is surely performed.

The lens barrier apparatus 35 will now be explained in detail. Asdescribed above, the lens barrier apparatus 35 is driven by the rotationof the rear lens group driving motor 30. The rotation of the rear lensgroup driving motor 30, and thus the operation of the lens barrierapparatus 35, is monitored by the CPU 210 based on the output signal ofthe rear group driving motor encoder. However, for certain aspects ofthe operation of the lens barrier apparatus, for example, in which onlythe position of a part is to be sensed, the function of the rear groupdriving motor encoder could be performed by another type of sensingdevice such as a limit switch.

As is shown in FIG. 75, the rear group driving motor encoder iscomprised of the photointerrupter 56 and the rotating slit plate 58. Therotating slit plate 58 is provided with a plurality of slits arranged atequiangular intervals on its surface. The rotating slit plate 58 isprovided on an encoder shaft 58f which is mechanically linked to therear lens group driving motor 30 through a gear train 42B. Inparticular, the rotating slit plate 58 is arranged to rotate by lessthan one full turn during any operations of the rear lens group drivingmotor 30. The rotating slit plate 58 is positioned with respect to thephotointerrupter 56 such that the rotation of the rotating slit plate 58causes the photointerrupter 56 to output a pulsed signal, the AF pulsesignal, in which a pulse is generated as each slit on the rotating slitplate 58 rotates past the photointerrupter 56.

The AF pulse signal is sent to the AF pulse input circuit 222 and theCPU 210 uses the signal to increment or decrement the AF pulse counteraccordingly. In this way, the amount of rotation of the rear lens groupdriving motor 30 is monitored by the CPU 210, both during movement ofthe rear lens group L2 and during operation of the lens barrierapparatus 35.

A description of how the rear group driving motor encoder is used forfault detection during the barrier opening process and the barrierclosing process will now be described with reference to FIGS. 55 and 56.

As described above, in the barrier opening process shown in theflowchart in FIG. 56, the rear lens group driving motor 30 is driven(driven to rotate in reverse) to open the lens barrier apparatus 35(S3603) and if, for some reason the lens barrier apparatus 35 does notopen fully (i.e., the AF pulse counter is not <100 at step S3611), therear lens group driving motor 30 is driven to close the lens barrierapparatus 35 (driven to rotate forward at step S3619), then again drivento open the lens barrier apparatus 35 (driven to rotate in reverse) apredetermined number of times, in this exemplary case, three times. Ifthe lens barrier apparatus 35 has not opened (i.e., has not been drivenby the required number of pulses) after the predetermined number oftimes, the error flag is set to 1 in step S3617.

Thus, in the lens extension process (FIG. 46), when the barrier openingprocess is called at step S1401, if the barrier opening process fails,the error flag is set to 1 and the lens extension process is notperformed (Y at step S1403). In other words, if the lens barrierapparatus 35 does not open in the barrier opening process, the movement(extension) of the lens from the housed position to a photographyenabling position will be disabled. That is, if the lens is at thehoused position, the lens will be extended only when the lens barrierapparatus 35 is open.

In the barrier closing process shown in the flowchart in FIG. 55, therear lens group driving motor 30 is driven (driven to rotate forward) toclose the lens barrier apparatus 35 (S3503) and if, for some reason thelens barrier apparatus 35 does not close fully (i.e., the AF pulsecounter is not <100 at step S3511), the rear lens group driving motor 30is driven to open the lens barrier apparatus 35 (driven to rotate inreverse at S3519), then again driven to close the lens barrier apparatus35 (driven to rotate forward) a predetermined number of times, forexample, three times. If the lens barrier apparatus 35 does not closefully (i.e., has not been driven by the required number of pulses) afterthe predetermined number of times, the error flag is set to 1 at stepS3517.

The barrier closing process (FIG. 55) is executed at step S1367 in thelens housing process of FIG. 44. In particular, the barrier closingprocess is only executed after the lens is housed and the housed code isdetected (Y at step S1327 or step S1361). However, if the housed code isnot detected at step S1327 or S1361 (i.e., if the lens does not reachthe housed position) due to some fault in the lens housing process, thebarrier closing process will not be executed since the lens housingprocess will time out at one of step S1315 or step S1337. Thus, the lensbarrier apparatus 35 is closed only when it has been confirmed that thelens has reached the housed position.

As described above, in the barrier opening process, a signal is outputin synchronization with the lens barrier opening operation and whetheror not the lens barrier apparatus 35 has opened without fail is judgedby detecting this output signal. Also, in the barrier closing process,whether the lens barrier apparatus 35 has closed without a failure isjudged by detecting a signal that is output in synchronization with thelens barrier closing operation. Thus, even in the case where the barrieropening/closing process does not end normally, the necessary processes(re-execution of the opening/closing process, etc.) can be performed andcontrol can be performed to disable subsequent processes.

Since the lens is not extended unless the lens barrier apparatus 35opens and since the lens barrier apparatus 35 is not closed unless thelens is housed, it can be guaranteed that the lens barrier apparatus 35will be open when the lens is at a position that enables photography(when the lens is not housed at the housing position) even when theopening/closing of the lens barrier apparatus 35 and the lens movementprocess for photography are controlled independently of each other.

A more detailed description of the mechanical operation of the lensbarrier apparatus 35 will now be provided with reference to FIGS. 94-97.

When the power switch 212 is turned ON, both the whole unit drivingmotor 25 and the rear lens group driving motor 30 are driven by a smallamount such that the barrier coupling gear shaft 92 is driven. Thisoperation causes the barrier driving ring 97 to rotate in acounterclockwise direction (of FIG. 89) via the sector gear 97a. Duringthe rotation of the barrier driving ring 97, the barrier driving levers98a and 98b, respectively, move the two main barrier blades 48b in atwo-phase opening process as described in the following.

From the condition shown in FIG. 39, the barrier driving ring 97 rotatesin the counterclockwise direction to move the main barrier blades 48bfrom a fully closed position towards an intermediate open position (thefirst phase). At the start of this rotation, because the boss 101 ispositioned in the first opening section 107a of the barrier drivinglever 98a, the wall face of the first opening section 107a pushes downon the boss 101 and the boss 101 moves towards the optical axis.Accordingly, the barrier driving lever 98a receives a reaction force inthe direction of the arrow A (see FIG. 96) from the boss 101 via thefirst opening section 107a. Although the reaction force in the directionof arrow A causes a clockwise rotation force (i.e., in the direction ofarrow A in FIG. 96) on the barrier driving lever 98a, the barrierdriving lever 98a will not rotate since the outer face of the engagingpart 109 comes in contact with the inner peripheral face of the frontend surface 20c of the first moving barrel 20 and the inner face of theengaging part 110 comes in contact with the outer peripheral face of thecylinder part 34a. The second barrier driving lever 98b operatessimilarly, due to the effect of the reverse lever 104, and will notrotate in the clockwise direction even when a reaction force from thecorresponding boss protrusion 101 acts on the wall face of the firstopening section 107a of the barrier driving lever 98b.

In this way, during the first phase of the opening process, the effectof the rotation of the barrier driving ring 97 is to "non-resiliently"drive the two main barrier blades 48b between the fully closed positionand the intermediate open position. That is, the main barrier blades 48bwill be driven according to the strength of the rear lens group drivingmotor 30 in order to overcome any external forces that may prevent themain barrier blades 48b from opening. For example, if the barrier bladesare accidentally splashed with a sticky substance, such as juice or thelike, the barrier blades will still open correctly.

As the barrier driving ring 97 rotates past the intermediate openposition, the boss 101 moves past an inflection point E (see FIG. 96)and enters the second phase of the opening process. The boss 101 entersthe second opening section 107b and the reaction force from the boss 101is now directed in the direction of arrow C (see FIG. 96) and tends torotate the barrier driving lever 98a in the counterclockwise direction.In this phase, although the counterclockwise rotation of the drivinglever 98a is not physically restricted, the force in the direction ofthe arrow C is less than the urging force from the first end part 105aof the torsion spring 105, in the direction of an arrow D, on theengaging part 109. Therefore, the barrier driving lever 98a will notactually rotate and the boss 101 continues to move towards the opticalaxis due to the effects of the second opening section 107b, therebycausing the main barrier blades 48b to rotate to the position shown inFIG. 91.

Thus, during the second phase of the opening process, the effect of therotation of the barrier driving ring 97 is to "resiliently" drive thetwo main barrier blades 48b between the intermediate open position andthe fully open position. That is, the main barrier blades 48b will beresiliently driven according to the strength of the torsion spring 105such that any external force applied to the blades will be resilientlyabsorbed by rotation of the barrier driving levers 98a and 98b againstthe spring force of the torsion spring 105 (this effect is shown forbarrier driving lever 98a in FIG. 94) so that the barrier blades 48a and48b will not break. Further, the barrier blades 48a and 48b willspring-back into position when the external force is removed. Similarly,when in the open position, the barrier blades 48a and 48b remainresiliently in position, such that if an external force is applied, thebarrier blades will be protected from braking and will spring-back intoposition when the external force is removed. A particular example isgiven below with regard to the closing process.

The closing process also has two phases that are similar to those of theopening process. From the condition shown in FIG. 91, the barrierdriving ring 97 begins to rotate clockwise towards the intermediate openposition (the first phase). At the start of this rotation, because theboss 101 is positioned in the second opening section 107b of the barrierdriving lever 98a, the wall face of the second opening section 107bpushes up on the boss 101 and the boss 101 moves away from the opticalaxis. Accordingly, the barrier driving lever 98a receives a reactionforce in the direction of arrow A' (see FIG. 97) from the boss 101 viathe second opening section 107b. Although the reaction force in thedirection of arrow A' causes a clockwise rotation force (i.e., in thedirection of an arrow a' in FIG. 97) on the barrier driving lever 98a,the barrier driving lever 98a will not rotate since its clockwiserotation is restricted by the contacting of the outer face of theengaging part 109 with the inner peripheral face of the front endsurface 20c of the first moving barrel 20 and the contacting of theinner face of the engaging part 110 with the outer peripheral face ofthe cylinder part 34a. The second barrier driving lever 98b operatessimilarly, due to the effect of the reverse lever 104, and will notrotate in the clockwise direction even when a reaction force from thecorresponding boss 101 acts on the wall face of the second openingsection 107b of the barrier driving lever 98b.

Similar to the opening process, during the first phase of the closingprocess, the effect of the rotation of the barrier driving ring 97 is to"non-resiliently" drive the two main barrier blades 48b between thefully opened position and the intermediate open position. That is, themain barrier blades 48b will be driven according to the strength of therear lens group driving motor 30 to overcome any external forces, asexplained above for the opening process.

As the barrier driving ring 97 rotates past the intermediate openposition to the fully closed position, the boss 101 moves past aninflection point E' (see FIG. 97) and enters the second phase of theclosing process. The boss 101 enters the first opening section 107a andproduces a force in the direction of arrow C' (see FIG. 97) that tendsto rotate the barrier driving lever 98a in the counterclockwisedirection. Again, although the counterclockwise rotation of the drivinglever 98a is not physically restricted, the force in the direction ofthe arrow C' is counteracted by the urging force in the direction ofarrow D', caused by the action of the first end part 105a of the torsionspring 105 on the engaging part 109. Therefore, the barrier drivinglever 98a will not actually rotate and the boss 101 continues to movetowards the optical axis due to the effects of the first opening section107a, thereby causing the main barrier blades 48b to rotate to theposition shown in FIG. 89.

Thus, during the second phase of the closing process, the effect of therotation of the barrier driving ring 97 is to "resiliently" drive thetwo main barrier blades 48b between the intermediate open position andthe fully closed position. That is, the main barrier blades 48b will beresiliently driven according to the strength of the torsion spring 105such that any external force applied to the blades will be resilientlyabsorbed by rotation of the barrier driving levers 98a and 98b againstthe spring force of the torsion spring 105 (this effect is shown forbarrier driving lever 98a in FIG. 95) so that the barrier blades 48a and48b will not break. Further, the barrier blades 48a and 48b willspring-back into position when the external force is removed. Similarly,when in the closed position, the barrier blades 48a and 48b remainresiliently in position, such that if an external force is applied, thebarrier blades will be protected from braking and will spring-back intoposition when the external force is removed. For example, if a child ishandling the camera and inserts a finger between the barrier blades 48aand 48b during or after the closing process, the barrier blades 48a and48b will be protected from breaking by the resilience of the torsionspring 105 and will be resiliently driven such that when the finger isremoved, the barrier blades 48a and 48b will move to the correct closedposition due to the force of the torsion spring 105.

With the lens barrier apparatus 35 as described above, each of theopening process and the closing process include two phases, during thefirst phase the barrier blades 48a and 48b are non-resiliently drivenaccording to the strength of the rear lens group driving motor 30 toovercome external forces and during the second phase the barrier blades48a and 48b are resiliently driven according to the strength of thetorsion spring 105 to protect against breaking. Thus, by selecting thestrength of the rear lens group driving motor 30 and the torsion springaccordingly, the operation of the lens barrier apparatus 35 is reliableand the lens barrier apparatus 35 is compact and easy to assemble.

Further, due to the resilient driving during the second phase of theopening and closing operations, the main barrier blades 48b and otherrelated components are also protected against breaking when the Mainbarrier blades 48b are set at a fully opened or fully closed position.If an external force in the radial direction is applied to close or openthe blades, for example if a child is handling the camera, the externalforce is relieved by the resulting rotation of the barrier driving lever98a against the spring force of the torsion spring 105 as shown in FIGS.94 of 95. In other words, during the second phase and when the Mainbarrier blades 48b are fully open or closed, the main barrier blades 48bare spring-biased by the torsion spring 105 such that if an externalforce is applied, the main barrier blades 48b will resiliently absorbthe external force rather than breaking and will spring-back to acorrect position when the external force is removed.

Furthermore, with the present lens barrier apparatus 35, since the majorcomponents of the lens barrier apparatus 35 are disposed in one area ofthe barrier driving ring 97, for example, the single torsion spring 105is positioned above or below a line joining the hollows 102 of the twomain barrier blades 48b, it is possible to position the sector gear 97afor driving the rotation of the barrier driving ring 97 in the remainingspace below or above the line joining the hollows 102.

Furthermore, since a reverse lever 104, which reverses the direction ofthe force of the torsion spring 105, is interposed between the torsionspring 105 and the barrier driving lever 98b, the barrier driving lever98a can be urged by the spring directly and the other barrier drivinglever 98b can be urged by the spring via the reverse lever 104. By thisarrangement, it is possible to dispose the barrier driving levers 98aand 98b and the torsion spring 105 in a smaller area on the barrierdriving ring 97 in order to provide space for the sector gear 97a. Thispositioning of the sector gear 97a ensures that the thickness of thebarrier driving ring 97 can be minimized to make the zoom lens barrel 10more compact.

The operations of the lens barrier apparatus 35 that are performed whenthe battery is set or changed will now be described. The initial settingor changing of the battery requires a particular control sequence inthat, when the battery is removed, the CPU 210 in the camera does notretain an indication of the current condition (open or closed) of thelens barrier apparatus 35.

When the battery is set or changed, the CPU 210 performs the resetprocess at step S0001 of the main process (see FIG. 41). In the resetprocess (see FIG. 42), steps S1101 through S1113 are performed aspreviously described and then the condition of the lens barrierapparatus 35 is detected during the lens housing process (step S1115)

Usually, at the start of the lens housing process (see FIGS. 44 and 45),the lens barrel is extended to the tele side until the currently storedzoom code is detected (steps S1301-S1307) However, in this case, becausethe lens housing process is executed from within the reset process, thelens barrel has already been extended to a position at which a zoom codein the range 2-6 is detected. That is, at step S1111 in the resetprocess the AF lens initialization process (see FIG. 43) is called suchthat the lens barrel is extended to the tele side until a zoom code inthe range 2-6 is detected. Thus, in the present case, the lens housingprocess quickly moves to step S1307 and then, in steps S1309-S1365 thelens barrel is driven to the housed position as previously describedherein. When the lens barrel has been retracted to the housed position,the barrier closing process is executed at step S1367.

In the barrier closing process (see FIG. 55), as described above, therear lens group driving motor 30 is driven (driven to rotate forward) toclose the barrier (S3503) and if, for some reason the barrier does notclose fully (i.e., the AF pulse counter is not <100 at step S3511), therear lens group driving motor 30 is driven to open the barrier (drivento rotate in reverse) at S3519, then driven to close the barrier again(driven to rotate forward) a predetermined number of times, in thiscase, three times. If the barrier is not closed fully (i.e., has notbeen driven by the required number of pulses) after the predeterminednumber of times, the error flag is set to 1 at step S3517.

If the operation of the lens barrel and the barrier are performednormally and without fault, the camera operates in accordance with thecontrol process described above as shown in the following examples.

If, when the battery is set, the lens barrel is at the housed positionand the barrier is closed, the lens barrel is extended to the wide end(zoom code 2) while the barrier remains closed, the lens barrel isreturned to the housed position, and then the barrier is opened andclosed once. Thereafter, the lens barrel is placed in a standbycondition at the housed position with the lens barrier closed until thepower switch is operated.

On the other hand, if, when the battery is set, the lens barrel isstopped at a position between the wide end and the tele end and thebarrier is open, the lens barrel is extended towards the tele side untilone of the zoom codes between the wide end and the tele end is detected(for example, zoom codes 206), the lens barrel is returned to the housedposition, and then the barrier is closed Similarly, the lens barrel isthen placed in a standby condition at the housed position with the lensbarrier closed until the power switch is operated.

According to the above-described operation, the open/closed condition ofthe barrier can be ascertained after the battery is set or changed.Thus, the open/closed condition of the harrier can be determined withoutproviding a specialized sensor for detecting the opening/closing of thebarrier.

As described above, if the battery is removed from the camera and theinformation concerning the open/closed condition of the lens barrier islost from memory, the open/closed condition is determined immediatelyupon setting a new battery by operating the lens barrier to open/close.Thus, even in the case in which only dynamic information concerning theopening/closing of the lens barrier is detected, the open/closedcondition of the lens barrier can be controlled without providing asensor or the like to detect static positional information of the lensbarrier.

Although the structure and operation of a camera with the lens barrierapparatus 35 of the present invention is described herein with respectto the preferred embodiments, many modifications and changes can be madewithout departing from the spirit and scope of the invention.

The present disclosure relates to subject matter contained in JapanesePatent Application Nos. HEI 08-012317, filed on Jan. 26, 1996, HEI08-032522, filed on Feb. 20, 1996, HEI 08-032523, filed on Feb. 20,1996, HEI 08-034126, filed on Feb. 21, 1996, HEI 08-034822, filed onFeb. 22, 1996, HEI 08-058335, filed on Feb. 21, 1996, and HEI 08-058350,filed on Feb. 21, 1996, which are expressly incorporated herein byreference in their entireties.

What is claimed is:
 1. A lens barrier opening/closing mechanismcomprising:at least two rotating barrier members, each of said at leasttwo rotating barrier members rotating about a pivot; a drive ring whichis driven to rotate about the optical axis; and at least two rotationforce transmitting links, each of said at least two rotation forcetransmitting links being supported on said drive ring and being providedwith an engaging part which engages with a respective one of said atleast two rotating barrier members; wherein said engaging part of eachof said at least two rotation force transmitting links is formed with; afirst section that non-resiliently moves said at least two rotatingbarrier members in an opening direction when said drive ring rotatesfrom a position at which said barrier is fully closed, to a position atwhich said barrier is opened intermediately and resiliently urges saidat least two rotating barrier members in a closing direction by a springforce when said drive ring rotates from the position at which saidbarrier is opened intermediately to the position at which said barrieris fully closed; and a second section that non-resiliently moves saidpair of rotating barrier members in the closing direction when saiddrive ring rotates from the position at which said barrier is fullyopened to the position at which said barrier is opened intermediately,and resiliently urges said pair of rotating barrier members towards theopening direction by a spring force when said drive ring rotates fromthe position at which said barrier is opened intermediately to theposition at which said barrier is fully opened.
 2. The lens barrieropening/closing mechanism according to claim 1, wherein each of saidpair of rotating barrier members has a boss protrusion at a positioneccentric with respect to said pivot, the rotation force transmittinglink has a cam groove into which said boss protrusion is fitted, andsaid first and second opening/closing sections are provided in this camgroove.
 3. A lens barrier opening/closing mechanism comprising:at leastone barrier member which moves through a predetermined range; a driveelement; at least one coupling element that transmits a driving force ofsaid drive element to drive said at least one barrier member; and aspring mechanism having a predetermined resilient force and acting onsaid at least one coupling element only during a predetermined portionof said predetermined range, said spring mechanism decoupling thetransmission of said driving force in the event that an external forcegreater than said resilient force is applied to said barrier member. 4.A barrier mechanism comprising:at least a pair of barrier blades; firstmeans for nonresiliently opening said barrier blades by at least apredetermined amount when said barrier blades are closed and are to beopened; and second means for resiliently and fully opening said barrierblades such that said barrier blades are spring biased against externalforces.
 5. The barrier mechanism according to claim 4, furthercomprising:third means for nonresiliently closing said barrier blades byat least a predetermined amount when said barrier blades are fullyopened and to be closed; and are fourth means for resiliently andcompletely closing said barrier blades such that said barrier blades arespring biased against external forces.
 6. A barrier mechanismcomprising:at least a pair of barrier blades; first means fornonresiliently closing said barrier blades by at least a predeterminedamount when said barrier blades are fully opened and are to be closed;and second means for resiliently and completely closing said barrierblades such that said barrier blades are spring biased against externalforces.
 7. The barrier mechanism according to claim 6, wherein saidsecond means forcibly opens said barrier blades by at least anotherpredetermined amount when said barrier blades are closed and are to beopened, and wherein said first means resiliently and fully opens saidbarrier blades such that said barrier blades are spring biased againstexternal forces.
 8. A barrier mechanism comprising:at least a pair ofbarrier blades, a projection being formed on each of said barrierblades; a drive ring; at least a pair of engaging members that have anengaging opening formed thereon, each of said engaging members beingrotatably supported on said drive ring; and a driving mechanism fordriving said drive ring; wherein said projection on each of said barrierblades is engaged with a corresponding one of said engaging openings;and wherein when said drive ring is driven said engaging openingsinteract with said corresponding projections such that during oneportion of said driving said projections are nonresiliently driven andduring another portion of said driving said projections are resilientlydriven.
 9. The barrier mechanism according to claim 8, wherein saiddriving mechanism drives said drive ring in a first direction to opensaid at least a pair of barrier blades and a second direction which isopposite to said first direction to close said at least a pair ofbarrier blades.
 10. The barrier mechanism according to claim 9, whereinsaid one portion of said driving is at the beginning of the driving insaid first direction or said second direction and said another portionof said driving is at the end of the driving in said first direction orsaid second direction.
 11. A barrier mechanism which opens and closes acamera aperture at the front end of a camera lens barrel, said barriermechanism comprising:a pair of rotating barrier members which open andclose said camera aperture, said pair of rotating barrier members beingcentrally and rotatably supported on a pair of pivots that arepositioned substantially opposite each other with respect to the opticalaxis, and are provided with a boss protrusion at a position that iseccentric with respect to said pivot; an opening/closing ring which isdriven to rotate about the optical axis; a pair of rotation forcetransmitting links which are pivoted on said opening/closing ring, saidpair of rotation force transmitting links being provided with anengaging part that engages with said boss protrusion of each rotatingbarrier member, and open and close said pair of rotating barrier membersupon rotation of said opening/closing ring; a single spring member whichis positioned on a part of said opening/closing ring at one side of aline that joins said pair of pivots of said rotating barrier members androtatingly urges said pair of rotation force transmitting links; and asector gear part which is positioned on a part of said opening/closingring at the other side of the line that joins said pair of pivots ofsaid rotating barrier members and drives said opening/closing ring torotate.
 12. The barrier mechanism according to claim 11, wherein areversing lever which reverses the direction of the force of said springmember is interposed between said spring member and one of said rotationforce transmitting links.
 13. A barrier mechanism which opens and closesa camera aperture at the front end of a camera lens barrel, said barriermechanism comprising:a drive ring; at least one barrier member; at leastone coupling element provided on said drive ring, said at least onecoupling element transmitting a driving force of said drive element todrive said at least one barrier member; a spring member provided on saiddrive ring, which resiliently biases said at least one coupling elementin a predetermined manner; and a mechanical connection part provided onsaid drive ring, to receive a driving force to allow said drive ring tobe driven, wherein said spring member and said mechanical connectionpart are provided on portions of said drive ring that are opposite toeach other in relation to said at least one coupling element.
 14. A zoomcompact camera comprising:a lens barrier having an opened and closedpositions; a lens barrier driving mechanism to open and close said lensbarrier; a motor for actuating said lens barrier driving mechanism todrive said lens barrier; an encoder which outputs a predetermined signalsynchronously with operation of said motor; first means fornonresiliently opening said barrier blades by at least a predeterminedamount when said barrier blades are closed and are to be opened; secondmeans for resiliently and fully opening said barrier blades such thatsaid barrier blades are spring biased against external forces; thirdmeans for nonresiliently closing said barrier blades by at least apredetermined amount when said barrier blades are fully opened and areto be closed; and fourth means for resiliently and completely closingsaid barrier blades such that said barrier blades are spring biasedagainst external forces.